I don't remember which thread it was, but the gist of it that with modern (non)sensibilities, not only is the concept of allegory is dead but the risk of being seen wrongly as an allegory for wrongthink means that everything needs to be as literal and plain as possible. I wouldn't be surprised if shit like the billion articles of "how Watto in Star Wars is antisemetic" is one of the reasons.
So no more cool aliens since they might be seen as racist, we can only have humans (which are comprised 90% from niggers), only humans are allowed to be evil and there will always be a non defined "human supermacy" that makes no sense.