Here's a story about another board I go to:
This board was not political in any way, just a few (maybe 25) friends who got together through another board. Anyway, everyone there used their real names and there was no banning allowed, so as to create a nice environment, like I guess what RWA wants.
About six months ago, some random guys started getting on there, posting under other people's names, posting pics of dead bodies, etc. No biggie, we just ignored them.
Then, when they weren't happy with being ignored, they hacked into the guy who owns the board's account and got not only his home phone # and address, but his parents' number and address as well (the guy's in his 30's, so his parents are probably in their 70's or so).
Long story short, they started making harassing phone calls, giving out their info on porn sites, other boards, telling people to harass them, etc. The end result was the board getting shut down and the guy pressing charges against them.
Point being, this was a board with about 30 members that wasn't listed on any search engines or anything. This board is 1000X more public than that one, and as such needs to be moderated with some care.
That said, no, people shouldn't get banned just because of their point of view, but I haven't heard about that happening yet, and I've been here from day one.