For people that claim that morality is something that is divinely bestowed upon us by [insert god(s) here], there are few teeny weeny little issues with the assertion of absolute morality.
1. It is Logically Absurd. Even in the assertion of absolute morality, the individuals must discern between his or her own morality, and then come to the conclusion that what they have deemed moral and immoral are moral absolutes that are either understood universally or divinely derived. However, as time and our history has shown, what is moral in one culture is not seen as moral in another, and what you are left with is multiple cultures, possibly sharing in the belief of absolute morality, but for different moral values.
2. No Justification For Moral Absolutism. Your bible? Your Torah? You Koran?
I don't think so. With the exception of a few fanatical and extremist denominations of the Abrahamic religions, we can see that modern day religious folks have a hard time stomaching the barbaric nature of their gods in parts of their doctrine. But the gods are where the problems lie. Why are commands of the god to be followed as though they are moral commandments? If morality is an absolute and divinely derived, what justification - or rather criteria - do we use to judge whether or not the god's commandment is moral? After all, if he gives us our moral code, it stands to reason that anything he tells us is good because he tells us it is good.
3. It Mistakes Objective Morality For Unfaltering Obedience. We can say left and right that there are universal moral codes that we follow, but this is simply is not true. If we had universal moral codes, they would be known universally. But as it is, we have individuals who seem to think that their subjective mindsets are somehow the result of a god who has pre-programmed them to do moral things while knowing to avoid immorality. Well, since all current evidence points to morality being a subjective and cultural phenomenon that has evolved over time, we see individuals using their individual decision making skills to create a black and white spectrum that pigeonholes the rest of us into their world of moral absolutes. If their god says being gay is wrong, being gay is wrong, end of story. But, when you have evidence that points to another answer but you still hold on to your world of absolutes, you have abandoned the rational realm for that of irrational absurdities.
The fact of the matter is, when you make a world of moral absolutes, you are basically saying "I decide what is moral and what isn't, and I use my personal beliefs to make those decisions." I don't even understand how one can even attempt to argue for absolute morality when there are literally hundreds of religions that cannot agree on what is moral/immoral. Hell, the denominations within the religion are a mess, too. One of the real issues with the ones arguing moral absolutism is this drastic alternative where there is no moral authority and mankind will run amuck without sky daddy there to protect us. I tell you what: prove to me that your set standards are the moral absolutes and moral values, and I'll eat my words. I'll eat them with salt and pepper, with some barbecue sauce on the side and mashed potatoes. Okay, I'm done