Unfortunately, people have funky ideas of what's amusing, especially fandom people. After all, look at the common fandom phrase: "Winning a fandom fight is like winning the Special Olympics - you're still a retard." Accompanied by a picture of someone with Down's Syndrome when it's in macro form. As someone who has worked with the mentally challenged (including lovely people with Down Syndrome), I find that extremely degrading, and I think it enables a certain attitude towards the disabled.

Thing is, people who are mocking are trying for the shock factor, and some of them think it is necessary to cross the line. I personally don't - I've mocked plenty of times without going the route of Bad Taste, and I've read a lot of amusing mockery and parody that wasn't of Bad Taste. But jokes about victims of genocide and the disabled qualify as bad taste, "sry 2 say".