Basically, emos are conformists that think by looking like all the other emos they're being non-conformist and showing their originality. I know I sound like I'm generalizing, but I too know a lot of emos from my school, (and am really good friends with a scene girl, which to me is like a variation of emo) and they all seem to fit into that category.
Unfortunately, the kids that cut themselves more often than not have really deep emotional problems, and I feel pretty bad for these people. But if they're cutting themselves to seem cool or to fit in, then I could care less how much damage they do to themselves.
[ChanseyMaster]