It's a nasty group, really. They're hated because of how they operate, what they've done, and how these things... aside from being damaging... go against what they claim to be all about. In some cases, they go REALLY HARD against what they claim to be about.
They're supposed to be about helping autistics, for instance... but only 4% of their budget goes towards actually helping those that need help. The rest goes towards things like cure research (for something that may, in fact, be incurable by it's very nature), advertising and stuff, and paying crazy amounts to their own members. And then there's the videos...
But rather than repeat it all here, there's this topic already: viewtopic.php?t=291604 where a number of people (myself included) posted recently about them and why we hate them (for example, someone in there posted some info on their spending habits or whatever you might call it, and there's stuff about their videos, and so on). That topic derails a bit after a time, but still, it explains enough about them to get the point across.