The input to the algorithm is literally three numbers: total words, total sentences, total syllables. If this counts as AI, then your thermostat or film camera feels pretty AI too.

https://en.wikipedia.org/wiki/Flesch%E2%80%93Kincaid_readabi...

Perhaps we could use AI to give us a score for how AI a given AI is

ChatGPT gives it a score of 0.

https://chatgpt.com/share/c1e700bc-7353-427e-a953-1e234f5e96...

Good data point, but a little bit biased.