I think the point of female-only classes is not to MAKE females train there, but to let those that prefer only females train there...and like we've talked about, probably as a lead-in to the regular classes. So women would not be 'banished'
against their will to it, and eventually those looking to it for self-defense against males will move on to the coed classes (I would hope).
For what it's worth, if I have a question about how I am doing a technique, I trying changing something each try/pay close attention to my partner's movement if it seems like they have it/and ask the instructor (unless I am partnered with my sensei); being 'raised' in a silent dojo I don't ask my partner. But that has never stopped the flow of incorrect or unwanted advice. Once a male on his first night kept telling me (laughingly incorrectly) how to do something, the instructor told him to stop, that (a) he was wrong and (b) I had plenty of years and knew what I was doing...as soon as he walked away, my partner resumed his 'teaching'
I usually find the only way to silence nonsence is to use a value-added throw while they are in mid-sentence, but you can't rightly do that to a beginner.