Not necessarily the best solution. Before voting, it would be a good idea to confirm that you are not a bot. If it is possible to set something like that up
I looked into it. I don't see any option to check if something is a bot in itch.io or not. The person could also use multiple verified accounts to bypass the check. There isn't much i can do except turn off the comment ratings. This may be temporary.
How about leaving it as it is? I've come up with another way of rating. Adding thumbs up and thumbs down emoticons to posts here? The effect will be similar