1. Go to Community Wishlist.
2. Select any wishlist entry with some comments made by other users.
3. Hover your mouse over the small box on the right side of the comment and click either "Hide" or Report".
4. Click "Unhide".

And nothing happens. the comment is permanently hidden and clicking "Unhide" and refreshing the page doesn't work.

How to fix this?

Not have it exist in the first place. Scrap the community wishlist. It's clear that it does nothing as games with single-digit (or close to it) votes have been accepted (e.g. Sally Face) while games with 1,000+ votes have been rejected (and no I don't just mean the one everyone wants to talk about lately). And that's games...don't get me started on the Features wishes...I know everyone here really desired GOG to sell DRMed Epic games through the new store on Galaxy 2.0...lol....