The same as any chauvinistic community - the advancement of people within at the expense of those without. They use sex but it could just as well be religion, race, language, political ideology etc.

I'd say they're pretty toxic because radical feminism is not the basis for a workable society. Other forms of community chauvinism can work, even if they produce undesirable outcomes (e.g. shithole Islamic countries still function even though they are shit - a rad fem matriarchy is just a bad meme that runs against evolutionary sex relations).