I can’t message them to ask about it because Itch.io doesn’t seem to have a private message option.
I just want to point out, that usually approaching people that give you a bad review is not a very good idea. This may not be possible on Itch, but I’d advice to avoid doing that if you are using other platforms that make this possible, especially in a private conversation.
As others mentioned, that is the life of an indie dev. In fact, this is the life of any creative person. There is no popular project out there with no negative comments/reviews. If anything, if your project has a mix of positive and negative reviews, then you are on the right step! Users are more likely to review a negative experience than a positive one.
At least this is my opinion. Try to find a popular youtube video with no dislikes, and I might change my mind :)