Gay people have invented, authored, and created for all of human history, largely under the guise of being straight lest they be shunned and cast out of halls of power.
No the persons comment was very much lumping the creation of Batman under this. Like, yes, the story is cool and very surprising given the circumstances. But that isn’t what the person you’re replying to is taking issue with.
What would this be called, gay-washing? I don’t know, I also don’t really care. I’m just pointing out what I see.