The part that sucks about it is that the radical/moderate divide means that a lot of people who would otherwise be friends do have to engage in a lot of public fighting, much of it out of genuine exasperation at each other.
I take it as a given that most people aren't going to support significant change, since many people are doing fine as it is, and, even if they aren't, change is scary. So there has to be room for various approaches to appeal to different groups, all pushing in the same general direction.