Kind of like Stalin, Mao, Pol Pot, Hitler.... oh wait, they were fans of moral relativism, Hitler a huge fan of Neitzsche, for example. I don't think you want to compare body counts.
It would be a good idea to try to back up your claims: 1.The claim that all these guys were fans of moral relativism. 2.The claim that their moral relativism was the prime reason for their cruelty.
Man, none of that was proof. Even the fact that you state that moral subjectivists are "nice" is a statement that is based on objective standards. If morality is subjective, then that statement loses all of it's argumentative power and you've said nothing.
First of all, whether it's a valid argument to him doesn't matter. Since you're a moral objectivist, and the argument was addressed to you, how you deal with it is what ultimately matters.
Second of all, no. Stating that people are nice doesn't necessarily have to be based on objective standards. To say that acknowledging that morals are subjective, means one can't say a person is nice, is basically like saying that if one acknowledges that morals are opinions, then one can't have a moral opinion. This is of course self-contradictory.
Godwin's law is an internet joke, not a real logical fallacy. It's funny, but likewise meaningless.
It's a very decent rule, basically telling people to stop acting like hysterical fanatics in debates. Not only is the comparison an ad hominem, it usually involves cherry-picking, correlation confused with causation and certainly an appeal to emotion. Lastly, that these comparisons can be conjured up no matter what it is you're arguing shows just how weak it is.
Objective morality does exist.
Again, if I steal something from you, you will state (at least to yourself) that I am wrong. When you state this, you're using an objective standard by which you determine if something is wrong or right.
1) If morality is really subjective, one would realize that actions which they think of as wrong are only their opinion.
Only? If you have any experience with online debate and real life you should realize that opinions are usually held very strongly. People adhere to their opinions just as strongly as they would any objectively verified observations, if not even more strongly. You seem to think that realizing that morals are opinions, suddenly makes them weak and willy nilly. It doesn't, human beings don't work like that.
Try to realize that accepting that morals are subjective doesn't suddenly make them disappear in thin air. My taste in music is subjective too, but realizing this fact, doesn't make my specific taste meaningless to me. I'll react equally strongly to my favourite music as I would had my taste somehow been objective. My morals and my taste in music is a part of who I am, and I can't just make them go away simply by realizing that they are subjective.
nevermind - wife's water just broke - see ya in a few days....
Wow, congratulations!
Peter