This is something which has long been said by many feminist groups, albeit usually without the “demonizing men is okay, actually” take. It was probably moderately useful once, but I’m not really convinced that it is anymore.
First, the problem with the idea of “men on one side of the line, women on the other, each of you take care of your own shit” is that, after the very basic stuff, both sides are going to come up with solutions which interfere with each other’s solutions. *Some* degree of crossover cooperation and agreement is necessary, otherwise you’ve got two groups playing different games with different rules on the same field and constantly punishing each other for following the “wrong” rules, leading to an almost literal “battle of the sexes”. That’s not to say that women shouldn’t primarily focus on women’s issues, and men should just continue to largely ignore men’s issues, but unless you plan to live on a separatist commune with like-minded people on Mars or Luna, you still have to live within the larger society - and if you are planning to do that anyway, why even bother with men’s/women’s issues?
And then, more to the point, the type of people who we *do* see calling for this? Virtually always gender essentialists. They’re not just men on the left, women on the right; they’re also tr*nnies on the side of your birth sex, enbies stop pretending you’re different/better than us. Or alternately, non-cishets, form your own tiny groups, and also if the two big groups are stomping all over you, you’re on your own. And then there’s the fact that a lot of them don’t care about how their solutions impact the poorest and/or racial minorities; such people don’t have anything to say about the “typical” male/female experience in their eyes and thus don’t matter. So even if it *was* a good idea, the kind of people who would likely end up controlling the conversation are the ones who absolutely shouldn’t be.
It’s hardly hopeless, but it could also never be so simple.