Denial of crimes against humanity, though, I see as a big mistake. I know, I know, we've all beaten the Holocaust to death... But when it comes to anti-capitalist and anti-comunist thinkers there is a great deal to talk about.
For example, anti-communists will tell you that Mao commit genocide during the great leap forward. Reasonable people disagree.
I, as an anti-capitalist, will tell you, that the quality of food sold in primarily black neighborhoods in the US is much lower than elsewhere in the country, that millions of blacks die as a result, and that this is an act of genocide against blacks. Obviously, a lot of white Americans would disagrees with me, and I think it would not be a good thing if they all went to jail for doing so...