Funnily enough I thought you'd probably remember events differently, ScottishMummy, but never mind. I think it's pretty incontrivertible, though, that the rad fem section was not asked for by the radical feminists, and at the time (when MNHQ floated the idea) most of us said we thought it was an attempt to marginalise and quarantine the radical feminist voices on mumsnet.
I also think there is a strong element of patriarchal expectations about women's style of discussion at issue. (And this bit is not aimed at you, SM: I get the strong impression you can more than handle a robust discussion 
). Some posters didn't like other posters getting angry about issues. And radical feminists are often angry, justifiably so, because there's a lot to be angry about - domestic violence, rape, FGM, forced marriages, women's marginalisation worldwide, unequal pay, etc. The list is huge. But according to the patriarchal world view, women aren't supposed to get angry, that's unfeminine. So when a woman gets heated or angry in a discussion, this is somehow taken as beyond the pale, and others (including some other women who have internalised patriarchal values about appropriate female behaviour) try to silence angry women, or dismiss them as over-emotional (actually, I always find it remarkable how articulate and able to step away from the personal and draw intellectual lessons of value from their experiences some of the posters on here are, especially some of the rape survivors). I still stand by the view that I hardly ever saw self-identified rad fems stoop to personal attacks, though. And some of the cases which were described as bullying behaviour simply looked like someone who didn't like being disagreed with.