Supreme Court Same Sex Marriage Argumet

[Aristocatt]

You are still missing the point.  When you use one example of extinction to justify your position, all I need to do is use another example of extinction to justify mine.  This is very basic.  Your original point was based on the principle of the matter, and not on the utility of it.  If you want to change your argument that is fine.  But we need to drop this ridiculous notion that potential extinction is a viable reason to undermine the social utility of an entire group of people, and recognize instead that a number of factors are at work.

The IVF argument and the under population argument are in fact different.  I am not accusing you solely of committing a fallacy of composition, I am accusing you of presenting a false narrative.  The IVF argument is also not a fallacy of composition argument.

I see.  You are endeavoring to argue I made a causal fallacy.  So I will respond to your specific fallacy and two other ones which I think comprise your single:

1.  The fallacy you identify appears to state an argument in one of two ways (please correct this if it is wrong) first it seem to say if there is more than one cause which may lead to a given outcome than we may not "undermine" a particular cause in regards to its tendency to a negative outcome do to the myriad of alternative causes.  By this argument we may not undermine guns in regards to them being used to kill people because people are also choked, stabbed, beaten, burned, starved, skinned, infected, drowned, electrocuted, and so forth.  Nor may we undermine any of the listed (or not listed) means by which people are killed because there is always another means.  Naturally I do not think this argument is tenable since it serves no other purpose than to say we may not identify any particular cause as negative in regards to its objective consequence.  Such ignores both the objective consequence of the cause as well as the subjective intention of the agent engaging in the action as a cause.  This would subsequently limit determination of the cause to a purely subjective valuation, whereby the particular is not discussed as a cause but as an act in itself to be determined as good or bad by the actor regardless of the impact it has or the intent the actor had.  (I would strongly caution going down this route of argument.  If you want to I would direct you to read https://atheistforums.org/thread-33523.html where we have already discussed it at length).  
No.  My conclusion was that if homosexuality is socially undesirable because it is a plausible cause of extinction, then heterosexuality is also socially undesirable because it too is a plausible cause of extinction.  This has nothing to do with saying that because an outcome has a set of causes, that you cannot make a judgement of said causes.  It only says that causes with the same, perceivable, likelihood of the same outcome, weigh such an outcome equally when making normative valuations. 
Second, if I am to take your argument as not meaning a myriad of causes, but rather as an issue of a sequence of actual or proximate cause than it would appear your argument is saying one may not undermine any particular cause unless that cause is the direct actual or immediate proximate cause of the negative outcome.  By this argument we may not undermine any initial cause resulting in the negative outcome of death because the initiating cause is not the direct actual or immediate proximate cause.  Once again such an argument is untenable as it would limit discourse to say the cause of death is dying, the cause of cancer is cancerous cells, the cause of rape is being raped, and so forth.  In short the argument becomes a continuum fallacy by which we must determine the exact moment the sequence of causes becomes the final consequence; the action just before the final consequence is then the only direct actual or immediate proximate cause which may be referenced as any other cause is only a initiate of another cause in a sequence of causes.
This is exactly the opposite of what I was suggesting.  You even recognized that my case against the heterosexual requires looking at the indirect causes.  This is why I am inclined to think you are being disingenuous.
2.  Fallacy of a Single Cause:  Similar to the first interpretation of the fallacy you point out it may be said that we never contended homosexuality was the single cause of extinction.  Rather it was the cause to which the focus of our inquiry was directed.  It may readily be said that any number of causes of extinction exists and that we would "undermine" all such causes due to the negative consequence that follows from them.  Thus, choking, stabbing, beating, burning, starving, skinning, infecting, drowning, electrocuting, and so forth as various causes of killing of people are denigrated due to the negative consequence.  It is further recognized the "undermining" of the causes is not limited to the agent, but most definitively in terms of its negative objective consequence.  Choking, stabbing, beating, burning, starving... is bad whether caused by an inanimate object or as the volitional act of an animate object if it results in the death of a person.  Thus, The existence of many causes does not invalidate the negative of a particular cause.  We may readily admit over-consumption leading to extinction is bad, while still maintain it is not the focus of our discussion and its impact as an alternative cause of extinction does not serve to eliminate recognition of other causes of extinction that are the focus of discussion.
Largely irrelevant to my point.  Your lack of attention to detail is not a defense of your position.  Saying, "I never said other things couldn't cause extinction" is not a defense.  It was very obvious you were making a point about homosexuality in relation to heterosexuality, and it was very obvious I was making a point about heterosexuality in relation to it's plausibility as a catalyst of extinction.  See my first line of red text to understand why this matters.
3.  Third Cause Fallacy:  Similar to the second interpretation of the fallacy you point out it may be said death is the direct actual or immediate proximate cause of extinction if and only if the rate of death exceeds the rate of procreation (I think we may agree on this).  From here the focus of my argument was upon the procreative side of the equation.  Holding all else equal (this is to say the rate of death remains constant) if we were to go along with Pyrrho and say homosexual intimacy is superior to heterosexual intimacy, such that the former is permitted and the latter prohibited, will we have a situation where the rate of procreation will exceed the rate of death?  The answer is no; in which case we may say homosexual intimacy (while not being the only cause) is a cause of extinction.  
This is a different one from the scenario I asked you about before breaking down why your argument is incoherent.  This is also an even more implausible scenario.  See my first line of red text.
Argument to over-consumption serves to take the death side of the equation.  Holding all else equal (this is to say the rate of procreation remains constant) if we say over-consumption is superior to under-consumption, such that we permit the former and prohibit the latter, do we have situation where the rate of death exceeds the rate of procreation?  The answer becomes not necessarily; simply because it depends on what we over-consume.  Over-consumption of a competitor will decrease the death rate, of a luxury will not increase nor decrease the death rate, while over-consumption of a necessity will increase the death rate.  As such we may say we should over-consume our competition for resources, it does not matter if we over-consume luxury resources, and we should not over-consume necessary resources as such will end in extinction.  Should we not wish to make distinction between competition, luxury, and necessity than we may say over-consumption as a whole leads to extinction based on the assumption we would over-consume all resources including necessary.
This is barely a coherent paragraph.  It is also largely irrelevant.  All that matters is you accept the plausibility that it leads to extinction.  Similarly, your argument rests on my ability to accept the plausibility that a catastrophic event that somehow disproportionately affects heterosexuals destroys all our medical devices, or destroys all of our energy production capabilities, and that furthermore, no homosexual is willing to procreate to keep the species going, and that no technicians and scientists exist capable of restoring IVF treatment.  The other scenario you provide assumes that if we make it okay to be gay in society, everyone is going to become gay, and not be willing to procreate.