Facebook isn't special; it's just a subset of the Internet. If the people at your college had had, say, a mailing list instead, and someone had sent that picture to it (thereby putting a separate, cacheable copy in every person's inbox), would you reason similarly that "he should have had control over this kind of thing"? Just because it's one website, not millions, doesn't mean that anything put onto it won't be leaked back out by bullies, trolls, rumor-mongers or busybodies. There's no such thing as privacy in a network where even a single person is less than 100% trustworthy, no matter the medium.

You should be able to 'come out' if you are gay without that kind of nonsense, presumably you have enough to deal with in a situation like that and your family should be supportive.

Especially your family.

As many have pointed out, this happens already in blogs and email, on twitter, in various forums, etc., and not joining facebook will do nothing to prevent it from happening on facebook.

But more importantly, if you don't want your friends doing X or Y to you on facebook, you have a very powerful method of ensuring that at your disposal: make it clear that you find this unacceptable when it happens. Over time, people get the message before making the mistake, and these expectations harden into social norms. Ultimately, relying on these social norms is much more robust than relying on technological solutions, in my opinion.