People really do seem to have it in for tents.
In the wake of OWS getting purged out of Zucotti park, this popped up in my tweetstream as a retweet:
@UKtraveleditor: Why must tents & long-term camping be part of modern-day protests. MLK & Civil Rights didn't need such tactics
Two things come to mind: one is that, actually, the civil rights movement certainly made use of much more disruptive occupation tactics. This is the 'sit in' protest. Activists would pick a target (best known example appears to be the Greenboro Woolworths) and occupy it in an attempt to stop other people from using it. The Greenboro protest went on for about six months. Yes, everybody went home at night, and no-one pitched a tent, but the tactic is markedly similar.
The second thing is that tactics change. The surprising thing about the sit in protests is how little resistance the protestors found - they could still enter and occupy months after the protest started. That's hard to imagine now. And the sit in technique was entirely novel in US political protests, coming out of Gandhi's non-violent protest against the British in India. I'm certain there were anti-sit-in voices on both the right and the left who wondered what was wrong with marches and letter writing.