The flaw in this plan is that about 44% of women voted for Trump - and if those 44% of women don't join the 4B movement, you've essentially got people on the left deciding to not have sex with the men who likely supported them anyway, the Trumpers banging out babies - and a perfect lens from which the right wing can say.... 'aren't feminists mental?' - it's basically a method for self-selecting more right wing voters.