Hang on, you want a section FOR feminists to talk about feminism and then you say that you are happy for it to be open to everyone - is that not a contradiction?
If you have an open debating forum you will get trolls and weirdos and creeps - most of them come onto Mumsnet just because it's called 'Mumsnet' and they usually head for the group they think will give them the most reaction and the most attention.
If you do not want to attract this sort of attention then the only option is to have a closed forum.
Otherwise every thread on Mumsnet should have a header warning people of trolls because there are equally sensitive threads such as those on bereavement, miscarriages, trying to conceive, breastfeeding, gay parenting etc - do their posters not also deserve some warning that trolls might be feeding?
The AIBU topic has a header because it's a general topic that is available to everyone and deals with every subject under the sun. The feminism topic is not. So if MNHQ put a heading over this topic, they would have to do so for every other topic - so why not just put a warning in the entire Talk section? Oh hang on, is this not a warning? "Please be aware this is a public forum and your postings are open for all to see."
This site is first and foremost a parenting site. The feminism is just a category within the site as a whole.
And as someone who has been the recent target of a nasty troll and has been a mumsnetter for 10 years (cough) I can honestly say that there are no more trolls on feminism than on any other topic. They come in cycles, you get a few all at once (probably because of a link on a website) and then it's the turn of another topic.
If you report vicious posts to MNHQ they DO delete that post and they WILL ban the poster. They don't always tell you what action they have taken to prevent that from being discussed all over the boards, but they do take serious action.
There have been nasty trolls on here since I can remember. The only course of action you should take is to click on report and then DO NOT FEED IT. Because I've noticed that the trolls get a lot of attention, which then attracts further trolls and word gets around that this particular topic provides great entertainment. So hard as it might be, you just have to pledge between you all to report and ignore.