No pun intended:
Well fuck.
They literally did just do this, almost tagged everything NSFW/Adult no longer appears in itch.io’s search, I just made a new account and specifically checked the ‘show nsfw stuff’ setting and… yep.
Currently I am only seeing like uh… 3 games.
There used to be 100s, probably more like 1000s.
They have not taken down the actual urls for actual games, but you have to know them directly.
Kotaku seems to have an actually decent overview, very recent: