He’s wrong because he’s not Gabe Newell. On a more serious note, the 404 report cited by the PCGamer article basically supports your point, though with the caveats that X and Musk are bad for other reasons and that those generated images make it into people’s feeds:

The major, uhh, downside here is that people are using Grok for the same reasons they use AI elsewhere, which is to nonconsensually sexualize women and celebrities on the internet […]

The situation on other platforms is better because there are fewer Nazis and because the AI-generated content cannot be created natively in the same feed, but essentially every platform has been polluted with this sort of thing, and the problem is getting worse, not better.