I think they are saying most attempts at diversity come from middle aged white guys and just end up being poorly done and so detract from the game/story.
Similar to how 00's electronic companies just painted it pink to appeal to women or why South Park added Token.
So arguing for more diversity within the companies themselves
You are far worse than the people you are claiming to act against.
Lots of people can feel something is a problem and struggle to articulate it. So you have to take people on a case by case basis.
OP talks about how they feel diverse characters are shoe horned in or badly written. Ask them to provide an example.
When they can't, then call them out. They are a bigot and deserve scorn.
If they can provide an example, help them understand the issue and use appropriate language.
Calling someone out who genuinely feels there is a problem doesn't stop them feeling there is a problem. These people will go looking for some who acknowledges their feelings.
Which is how you make a bigot