Of course, if you're saying society at large is irrational I pretty much agree... but within the context of social expectation, I'd say it's pretty rational to compute that your contribution is more likely to land once a movement has already started. If anything, those who first begin the movement are the most irrational (since the likelihood of success is much lower compared to the personal cost to the individual).
In other words: if you live in an irrational system, the only way to be rational is to behave irrationally.
EDIT: Italicizing.
Same with calling protestors "irrational" -- maybe to your point of view, they are but this is not an objective statement by any definition of the word.
Sure, but that's not what I described.