One: The likelihood that Zak has been falsely accused is so small at this point as to not be worth entertaining. You can argue this point, but you'd be wrong.
Two: The point of this kind of lawsuit is not to sue for "damages", it's to cause damage. Win or lose, these women are going to have to pay hand over fist for legal fees that they will not get back. The point is not recoup professional losses; it's to silence them, and anyone else in the future who might consider calling out their more powerful abusers in public.
Three: How do I know point two? Because there is basically zero chance that Zak does not land on his feet very shortly after all this blows over. Even if it never actually does blow over (which would be nice, but is a pipe dream at this point) there are more than enough people who would more willing to support Zak by buying his products over this that he isn't going to have to worry about it. Because there are a lot of people who really, really, suck. And whole hell of a lot more people who just don't care. Which is almost more tragic.
Four: Meanwhile, SLAPP suits such as these tend to either financially ruin people or force them to back down. Either way they lose. These women are having their lives ruined when there's at least, charitably, a 90-95% chance they've been telling the truth the entire time and warning the community about a known abuser. You're telling me you're okay with that?