Are you okay with your (or your partner's) vajayjay?

[TheRocketSurgeon]

The penis, like the vagina, is just a body part. It is not icky, it is not gross. It's just a part. We're systematically taught to be grossed out by them and/or ashamed of them, by a culture that is rooted in anti-sex religious ideologies, even if we don't easily spot the programs as they operate in our own minds. However, several books on sexual psychology go into pretty good depth on this sexual-cultural pathology.

As for the supposed "grossness" of putting a penis in your mouth, you're a couple of million times worse-off (literally, from a bacteria-count point of view) kissing a girl's hand as putting a penis or a vagina in your mouth, whether or not they are all washed. Human mouths are not much better, and are in fact worse than our genitals. These are some of the amazing things I learned in Microbiology 211. After learning just how dirty our hands and mouth are while testing various portions of the body (even did butts... yep, swabbed that sphincter!), despite our class's best efforts at brushing and rinsing mouths, and washing hospital-scrub-style with antimicrobial soap in the case of our hands, I did some quick math and realized that our genitals were significantly cleaner than the mouths they were going into.

So all the "eww" is all in our minds. You want to really be grossed out? Look at cheese or yogurt on a microscope slide, spread very thin and gram-stained so they show up. Trust me, it's a Bad Idea™.

Point is, while I'm not attracted to men sexually, from a "grossness" point of view, you're much, much better off sucking a dick than a finger. No joke.

How about the psychological eww of doing something sexual with someone you're not comfortable having sex with regardless of orientation??

I completely disagree with you. Eww isn't always about germs. People have a right to be uncomfortable with the thought of a sexual experience that makes them uncomfortable. It's not bigoted or immature.

It's hard to give a gender based example because I consider myself pansexual. But I would compare it to the thought of a sexual experience with someone who I am not comfortable. Eww. Yes the thought I have is eww. Some stranger who gives me a creepy vibe, the thought of doing anything sexual with them is eww to me. I don't think that makes me immature.

FFS... really!?! DAMN IT.

I am not making the point that I expect a person to wish to have sex with someone they are not attracted to. That has never been my point. It has always been a red-herring/straw-man version of my argument, and I have repeatedly tried to explain only to be FUCKING IGNORED. GODDAMNIT!

The question I have been addressing is why we personally consider certain acts "gross", or "eww", as opposed to simply not being motivated by our own instincts to perform those acts. 

And I have never called anyone immature, here.

Being, as you say, "absolutely repulsed at the mere thought of a sexual activity with a man" is not the same thing as "absolutely repulsed by the sex act of being with men".

I too am repulsed by a number of women, many of whom would be considered traditionally attractive, since personality has a great deal to do with my own sense of sexual attractiveness in a human being.

The reason I mentioned the germs issue was simply to illustrate that there's no biological basis for considering one act disgusting, when most of us have other acts we consider normal which are in demonstrable fact more physically disgusting, on a germs basis. And yet, many people will claim that the act of gay sex is itself  a disgusting, degrading thing for a man to do (this is not his position, I wish to be clear, but it is a common one I encounter in such discussions), despite there being no rational basis to consider it so. An instinctive negative reaction to something without rational basis is a phobia. That includes homophobia and certain forms of mild racism.

I made the parallel with this mild sort of homophobia and the sort of mild racism people sometimes feel when they have an instinctive, phobic reaction to a person they have been taught is "dangerous", as in racial or ethnic or religious stereotypes, yet who would not recognize on their own that their reactions are indeed racist, despite the inaccuracy of describing a well-intentioned but badly-reacting person as "a racist person".

My entire goal here was to get him to try to evaluate why it might be that he considers the act  to be "eww", as opposed to simply not wishing to do it. Disinterest and disgust are two very different things, and I think "well I have never been attracted to a guy" is a weak excuse. I too have never been attracted to a guy, but I don't think "eww" at the idea. 

Indeed, he did  evaluate his position, and upon reflection clarified that he would certainly consider that act if he found a man attractive. It is a reasonable answer. Your strawman versions of my argument would mean I am calling myself and any other straight guy a homophobe on mere basis of not desiring  to have sex with men, an entirely different question. As should be apparent by now, I strongly resent having both my decency and my arguments misrepresented in this way.