That's exactly the problem and exactly why it's so prone to abuse.
When someone on itch.io leaves a review, anyone who's following them can see that review in full on their feed. It's clearly not intended to be private information since it's straight up published to anyone who decides to follow you. (Of course, almost nobody knows this because absolutely no documentation exists for anything regarding reviews)
That is certainly one way of handling it, which is part of the reason this is so frustrating: Many, many sites have implemented working solutions to this problem to the point that it's an industry standard.
Itch.io doesn't even require a captcha to make a new account.
Nothing being asked for here is revolutionary, nor would it necessarily require huge amounts of effort on part of the itch.io development team. Expensive anti-bot software certainly exists, but it's almost assuredly unnecessary for this site.
I'm quite sure this could be fixed with a minimal amount of work, but at this point I'd just be happy getting these malicious ratings taken down and some sort of answer from itch.io at all.
