I consider myself a radical (in lots of ways, not just regarding bikes). I'm not angry or cynical or violent (most of the time). I just ride my bike, and I love it. I tell other people I love riding my bike. I always ride with a big, fat, ridiculous smile on my face. That is the best advocacy there is. And honestly, I think it's pretty radical. The militant connotation of "radical" is all mixed up. That's not radical, it's just grumpy. Imagine doing something you believe can change the world, plus it makes you happy! That's radical. I always think of that line "A revolution without dancing is a revolution not worth having." Truth, that.
You don't have to be angry to be radical. You just have to put your whole heart into what you do.