Yeah, the problem is that you are relying on free contributors, these free contributors will get discouraged if your ideas can just be stolen by ChatGPT as their idea for a solution.
You don't go to SO to crowdsource creative ideas. It's for very specific one-off questions that many people will likely find themselves asking at some point.
For some reason, they don't. Honestly, I don't understand why, but there is a cohort of people out there who are ok with it.
If one becomes Reddit moderator then from day 1 they knew Reddit will benefit from them. If they didn't want it, they would not become one. When this changed (say Reddit closed their API) the moderators got really upset.
But when people posted on StackOverflow, they expected that their work is used by fellow humans, and that they get recognition for their hard-worked answers (even if it's just their name in the rank table). When this changed, people got upset.
Either way, I'd expect people who joined StackOverflow after this deal is announced are not going to be upset. But they are the minority, given how long SO has been around.