The argument does exist. This article by PEN America is one of the most widely spread ones and largely misrepresents the situation. It’s based on a PopSci article with a similar headline, though the contents of the article tell a rather different story.

Nothing really says out loud what’s going on: Republicans enacted an extremely vague and unrealistically short deadline book ban as part of a bill (that does some other stuff like removing AIDS education), forcing schools to either throw out every book that might be vaguely suspect or resort to funny measures like this. This school’s use of ChatGPT was purely to save books that were on a human-assembled list of challenged books, to reduce the negative effect of the book ban, while being potentially defensible in court (remains to be seen how that’ll work out, but they made an “objective” process and stuck to it - that’s what matters to them).