I doubt it's OpenAI. Maaaybe somebody who sells to OpenAI, but probably not. I think they're big enough to do this mostly in-house and properly. Before AI only big players would want a scrape of the entire internet, they could write quality bots, cooperate, behave themselves, etc. Now every 3rd tier lab wants that data and a billion startups want to sell it, so it's a wild west of bad behavior and bad implementations. They do use residential IP sets as well.

Stop just making up excuses for these companies. Other comments on this story have showed the bots are using openai user agents and making requests from openai owned ip ranges.