These protestors take to the streets and actively stop people from getting to work (or, say, a hospital) in an effort to raise awareness of bikes, under the guise of some kind of "take back the streets" campaign.
In plenty of "demonstrations" like this all around the world, there have been reports of groups of bikers banging on cars and shouting at the motorists (not to mention the fact that, to begin with, they're obstructing traffic). Popular protest groups, like Critical Mass, can be totally peaceful and responsible, but a lot of other groups are dangerous and idiotic, because that's what happens when you form a mob.
This also happens.
The second group of bikers that I can't stand? Hippies, obviously. Understand that I'm not talking about formal hippies (they of the peace-loving, drug-taking variety); I just mean "hippie bikers," the kind of people who not only bike, but explain to you that they bike because of how much better it is for the environment, man. It's not that what they're doing is wrong, it's that they're so self-righteous about it, like every admission of "I like to bike" is immediately followed by "because I just want to do my part to save the Earth, no big deal. We've only got one Earth, you know? Like, I'm not a big 'environmentalist' or anything, but it just made sense, you know? Why not be the one guy who isn't burning up fuel all the time, right? My carbon footprint is NOT going to be tire tracks."
Well it is, but of a different kind. Anyway, shut up.