It never occurred to you that a number of these 'conformists' are also just doing it because they... like to do it, not because they want to fit in?
I've been called emo before because of my hairstyle, my square black-framed glasses, and... well, that's mostly it. It was never my intention; it just happens that both look good for my features.
I tend to think non-conformists, who label themselves as non-conformists and are so pleased over their non-conformity, are the worst types of conformists. People who are strange just to be strange, ultimately going against even their basic nature just because they find it more interesting.
That said - conformity has been considered a throwback to our herd-based survival instincts. Fitting in, if you look at, say... zebras, is a good way not to get your butt savaged by some particularly hungry lion. Non-conformity, like a purple zebra, just made you the tastiest snack in sight.
I think conformity in the more "evolved" population today is neither here nor there. A lot of people see it where it isn't, in a way. Take a hundred people. Seventy people love Starbucks; thirty people prefer smaller chains, or no coffee at all. Bam - Starbucks is beloved by the "sheep," a bastion of conformity, etc, etc. Shrink it down, though. Take ten people. Five of them like comedies, six like action movies. Suddenly, liking action movies makes you a conformist, because the majority of the group likes them.
Nevermind that you just LIKE THEM because YOU DO. You are now a conformist.
I think conformity and the concept of a conformist is an irrational generalization, probably based in the statistics of what people do or do not like, and rarely seems to have anything to do with the individual. That being said, on the flip side of my statement regarding non-conformists being strange just to be strange, some people conform against their better judgment, denying aspects of themselves that they shouldn't. It's also where we get manners and social etiquette from (which differ between countries), why people say "thank you" and "please," and common human courtesy.
So. Yes and no. Conformity, as it's perceived, has its uses, but it's as much an illusion as non-conformity. Everyone makes decisions and lives with them on a personal level. S'all there is to it.