That was one of my worst experiences related to posting on forums.
Interestingly, my first experience with forum posting also did not go well. I stopped visiting the forum when people started trolling me. I was humiliated for being "Asian."
Racism is very common, in the real world as well as the virtual world.
Seriously, it was sad seeing what then did. Someone being from another race probably an Asian like you doesn't mean the person is a racist. It shouldn't warrant for the person to be treated as a racist when he or she haven't done anything to peg him as a racist. They were totally wrong.