dw4i2, if developers notices people are abusing from the comments on their page, they can either completely remove it, or change to a community based project, which is much better than having negative comments on the store page degrading their work. The Itch Team was really smart to think ahead about these possibilities.
Itch.io is a great place to publish games, but it's not everyone who can make it to the top, so it's more likely to happens with someone who's outstanding somehow, which awakens all sorts of feelings on direct competitors.
These countermeasures can't prevent harassment at all, but it can hinder most attempts and save any developer from massive review bombing consequences in the future.