I really didn't want to get into it and have to try to work out how to say it diplomatically (and even so, I fear I'll get accused of being dismissive of women's issues for saying it), but since you've already gone there and aren't pulling any punches, I will say, I had a similar thought as you. The timing of it, whether accidental or not, is weird as hell. The accusations could be entirely true, exaggerated, false, or anywhere between, but there is no time for people to sort that out properly literally on election day. And it's not as though PSL is gonna win the presidency and someone needs to call them out to make sure they don't gain immense power and abuse it. In this election, they've always been a fringe "closest thing to something truly 'left' to gain popular support and build a movement at all" and electorally, is mostly just a way to spread a "leftist" message. Tossing around "what's up with, I heard a rumor" type statements at a time like this, when they're going to be at the height of being seen at all throughout all the erasure a party like them faces in popular media, is bizarrely naive at best.

Similar happened with the green party recently (not originating on here, mind) and though I have little desire to defend them considering I never expected them to be aligned with folks like us in the first place, the timing of it was also odd. After a lot of hearing little about them policy-wise one way or another, the green party VP running has a statement extracted out that makes him sound like he has anti-trans views. Maybe he does and it's important to know, but if there is one thing US electoralism is a well-oiled machine at, it's smearing political candidates. And when it's coming for candidates who in the best case scenario could have their party win 5% or whatever for funding, it's all the more to me like, "We're doing this right now? Is this supposed to be principled?"

I could understand if we were talking about candidates who can actually win the presidency, but like, what exactly is the goal of bringing it up right now other than to get people to hesitate voting for a third party and help undermine any attempts to put a wrench in the dual party structure?

Even as little as a week ago would have been better. At least then there'd be some time to go over what is known. And if this was already known and people were waiting around to bring it up until now, that's just straight up the opposite of helping; not helping women and not helping organizing efforts either.