Is it true that there is no absolute morality?

[Jenny A]

I've seen people say a lot that there is an absolute morality, but it seems to me that there is not. For example, some people say that killing is ultimately wrong, but there can be no reason why one thinks killing is wrong, other than personal desire. Personal desire is not quantifiable, therefor it's an arbitrary measurement of a person's feelings. 

It would seem were it not for this problem, there wouldn't be religion, which tries to solve this problem through dogma, and the imposition of an imaginary creator of whom punishment is inescapable. It would seem to me, that all morality is nothing more than dogmas, whether it be social norms or enforced laws. 

How does one cope with knowing that all morality is arbitrary, and say that one respects morality beyond being blinded by dogmas, or simply appreciating the geometry of such arbitrary systems? on a purely intellectual level. The alternative is, of course, "psychopathy", where the dogmas and appreciation of arbitrary systems is absent.

By cope, I mean cope with the fact that the systems in place are arbitrary, so there's no one system which can ultimately bring about the best of humanity. Without an objective morality, of which one could appeal to every person through reason, there is basically only wars and dogmas that struggle for dominance.

The basic mistake you are making is in assuming morality is a monolithic whole. Most very basic moral principles are almost universal among humans. Humans who violate them then tend to define thier victims as others (not quite human) or to provide other justifications. Generally they don't challenge the moral rule itself. Morals that fall into this category include thou shall not murder, steal, batter, rape, or lie. Societies may tweak the definitions of murder, steal, batter, rape, and lie, but the basic concepts appear universal. As such they are not arbitrary. Further they appear necessarily to community living which suggests they have an evolutionary function, and are thus not arbitrary. Lesser rules such as not deceiving others or keeping promises are also near universal for similar reasons.

On the other extreme there are wholly religious or patriotic prescriptions like thou shalt not burn the flag, eat meat on Friday, work on the Sabbath, worship idols, eat pork, take the Lord's name in vain, get this tatoo, etc. These are pretty arbitrary. They are a good means of broadcasting tribe and alleigance, but don't seem to have any other real function. And the mere fact there is a rule, any rule, would perform the same function. The societal need to have a couple of these appears universal but what they might be is arbitrary. Often these rules conflict in that following a patriotic rule conflicts with a religious one, or vis versa. Tribal allegiance appears near universal, but how to demonstrate it approaches arbitrary.

In between are rules made by societies for the good of society, or at least for the good of the rules makers. These aren't arbitrary as they do have a purpose beyond tribal identity, but they aren't universal either: drive on the right (or left), pay your taxes, don't vote twice, don't pollute, don't discriminate, use approved electrical equipment, don't hunt out of season, etc. Such rules tend to have a reason and so aren't arbitrary, but they aren't universal either. People may in conscience disobey some of them without feeling a moral twinge but society would be shattered if even 10 % of people ignored 10% of them.

Notice that all morality tends to have to do with people getting along with or signaling to other people. Cannibalism, murder, rape, and theft, among other species isn't necessarily immoral especially if the species is not social. The concept of morality is social and evolutionary.