Meh, I'm straight edge (apart from the odd sip of booze), but not to be part of any movement.
I like having control over myself, don't need to spend a shit load to have a good night out and like being healthy. Plus, members of my family have died from liver failure and lung cancer, so I'm not gonna follow in their footsteps.
As for the superiority thing, when you're completely set apart from the peer pressure that goes with most recreational drugs, and the stupidity that often goes with taking them, it's hard not to look down on them. If some guy was stabbing himself repeatedly in the arm, it's difficult not to feel superior, and the same is true with booze, fags and other drugs.
Personally, I've never felt like I was missing out on anything by anything by being straight edge. Anybody who feels like they need to do this stuff is a moron in my mind...