I think this rule was established because otherwise people would hide NSFW games then search for their own and complain that they can't find them.
Viewing post in Please let me toggle NSFW visibility
That is what I assumed too. But it is a troublesome implementation.
It is better imho to instead put this information (account has uploaded a nsfw game) on the button to hide nsfw content in the shape of a huge disclaimer that appears when you do change that check box to hide it. And every time the account updates or publishes nsfw games the setting would revert to show nsfw content.
I read this particular complaint in several threads, so I believe this is an issue.