This statement does not logically cohere. "We can spot it because so many people make it easy to spot." You don't see how this is just petitio principii in action?
To fully disguise LLM prose, you'd have to rewrite it entirely, and if you were going to do that, you wouldn't be the sort of person to use it in the first place.
Maybe some people stop reading LLM slop purely because it violates their moral principles or whatever but most people bail out because slop is mentally painful to read. If you are a human and you write like today’s AI find a different writing style, not because reads like AI, but because it reads like shit.