I also regret that you feel scared Grace but having seen a few threads you've been on here, I do see why.
I don't think we can dismiss that some regular Mumsnetters feel intimidated from posting on this board. The reasons being given are pretty varied, but the main ones seem to be a lack of intellectual confidence, being harangued for their posts when they wanted a debate, not an argument - and a couple of posters have said that their posts are always ignored.
I've seen that too and would also add that some of that happened to me on a recent thread on this board. If lots of posters are making those observations, not to mention the possibility that there are lurkers who really are too afraid to post even on a thread that invites their concerns, then I do think it's a problem that we can't overlook.
However, I think it's also true of AIBU and there might be other boards that posters also find scary. I think it's really welcome that the OP here has had the courage to start a thread about it.
I think we all accept that trolls and shit-stirrers are going to get short shrift if they post on any board, but I think we'd be disingenuous if we ignored the testimony here that posters who tend to be regular, respected contributors on other boards, feel they've had a particularly hard time on this one.
If the effect of that is to deter contributions from a wider sample of posters, then I think we should listen to posters' concerns and instead of getting defensive, take the sort of positive action that we've seen today e.g. starting a questions/views thread about the porn industry, the "welcome" and Introduction to Feminism thread. They are all really positive, helpful actions, but that atmosphere needs to permeate all the threads, IMO.