Since I noticed that incest was one of the topics games were being premanently removed for, I searched google ( incest site:itch.io/c/ ) to look for collections of incest games to try to quantify how many games might have already been removed, and found a lot of collections with links leading to suspended projects (easily 100+). Now, only a couple of hours later, all of the collections I looked at are returning 404 errors.

I don't think all of those different users would have happened to delete their collections at the same time, so I can only assume itch is also deleting collections if they contain a lot of games that are now restricted.