This has been asked several times. I would expect it to be blocked in recommendations, but not in general listings. But the feature only works for comments and only hides them with a button making you wonder who it is that is hidden there.
But you can block listings by developer on client side. Use a user style extension and use such a style.
@-moz-document domain("itch.io") {
div.game_cell:has(a[href*="//username1.itch"] ) { display: none }
div.game_cell:has(a[href*="//username2.itch"] ) { display: none }
}
Maybe use a better url, else it will work on your library as well, if you do have some of that dev, but only do not want to see the stuff in listings.
If you have tampermonkey, I have a script to do this more conveniently. It is the browse ignore list script.