I don't understand why they would want to remove their code instead of wanting it to live on and further help more people through AI. Just because OpenAI charges $20 a month? It takes a lot of electricity to produce results from AI. Just seems shortsighted on flimsy principle. If it were me I'd wait for the lawyers to sort out what SO and OpenAI are doing with CC-By-SA instead of making a big stand about it on the internet, but I can sort of get it I guess.
Edit: I called it flimsy principle because it's not clear that CC-By-SA prevents this until the court rules