I see so many frothers warning the poor wimmin off who dare to engage with men and caped crusaders deciding who mn is for
I'm not really quite sure where to start with this 
I don't think any of us who are talking about the issue of perverts/sleazy posts on this topic have an issue with engaging with men. I'm sure there are many topics and posts where I have engaged, quite happily, with male posters.
I do, however, have an issue re engaging with perverted posts and posters. As do a lot of other posters here. You do them a grave injustice damning them as 'wimmin'. (Interestingly, unless I'm misreading your username, you are a woman too, are you not?)
And disagreeing, or robust debate, does not equal 'frothing'. It's like listening to misogynistic blokes dismissing women talking as 'banter'. You should know better than that @Janiie.
And 'caped crusaders'?! I am no hero, and I'm sure the other posters here who are objecting to sleazy posts/posters don't feel like this either. Nevertheless, there is a problem with people who think that they can come on to Mumsnet and post sleazy stuff. If that makes me Batman for calling it out, then 'go me!'
Why are you so worried about posters on Mumsnet calling out the perverted? What difference does it make to you? Do you feel it impinges on your freedom to post? Or do you feel, somehow, empowered, by siding with the perverts and sleazy posters?