itch.io

This is the first time I've ever heard of that game. I don't deny that it might be popular within its niche, but it's not a game that everyone knows, so I wouldn't assume the staff is familiar with it.

You can check the exact rules here:
https://itch.io/docs/creators/faq#is-adult-content-allowed

Over the years, what I've seen is that Itch has several rules, but they don't actively enforce them. For example, the rules state that you must have all the necessary copyright permissions for the games you publish, and if you search, you'll see many games based on content from companies like Nintendo, which obviously aren't uploaded by the people who have the copyright permissions.

I'd say the staff trusts that people will follow the rules and tend to act more when someone makes a report than actively searching for those who don't comply with the Terms of Service.

Itch's staff is very small; on the one hand, I doubt they have the human resources to actively enforce the rules, and on the other hand, it also gives developers some freedom, since it wouldn't be pleasant to have the staff reviewing every illustration or line of dialogue in your games.