He's probably referring to the fact that certain companies have been effectively blacklisting mods that they judge to have unsavory content. Sometimes these aren't the developers themselves. In the most extreme cases, for example, this was as ridiculous as blacklisting mods that enabled players to choose a gender in games where the character creation screen was limited to "body type". Nexus, the largest online modding community separate from the Steam workshop, did this:
Hello again, paradox of tolerance, my old friend.
www.pcgamer.com
That has become an agenda (not permitting choice of gender) that certain major western game companies have tried to push as a new norm. That's how far gone western game developers are. Meanwhile, eastern companies still focus mainly on prohibiting mods designed to help players cheat in MP modes.