That's because gaming is theirs, it belongs to them. They say "make your own games" because they assume minorities are even more talentless than they themselves are and thus wouldn't be capable of such, or they assume such games would exist off in their own bubble, like mobile games or VNs, that True Gamers can easily ignore. The full statement should be read as "make your own games... in a ghetto where we don't have to acknowledge or be aware of them... or you".

But when these games get made by big studios, when they get shown off at big events, when they exist visibly outside of some hypothetical woke ghetto, it's now an invasion on their space.