For the longest time, writing was more expensive than reading. If you encountered a body of written text, you could be sure that at the very least, a human spent some time writing it down. The text used to have an innate proof-of-thought, a basic token of humanity.
Now, AI has made text very, very, very cheap. Not only text, in fact. Code, images, video. All kinds of media. We can't rely on proof-of-thought anymore.
This is what makes AI so insidious. It's like email spam. It puts the burden on the reader to determine and sort ham from spam.