that is not correct, you can search for the same content using another search engine like google.
for example, take the name of a game with adult content and google with site itch.io and you will find it (with or without an itch account)
What I understand is that the idea of hiding the content and having a warning window is to prevent someone from mistakenly accessing said content, not that it is blocked.
It seems to me that the system works perfectly for what has been said, which is to hide the content, but not block it.
You could further limit access to such content, but that is a decision of the itch administration.