I think a lot of it actually comes down to the perception of where the content came from. I brainstorm and riff with AI all the time, but I know what I am communicating with, I don't get the same sense of ickyness. Blogs and books and all these things that are claimed be to written by a human, but are actually just AI, is frustrating. Honestly, the content may be perfectly fine, but I feel something irritates humans when they think they have been deceived.