I'm somewhat skeptical. What if LetsEncrypt decided to misbehave tomorrow? Would the browsers have the guts to shut it down and break all sites using it?
The conventional wisdom used to be, (normal) porn makes people more likely to commit sexual abuse (in general). Then scientists decided to look into that. Slowly, over time, they've become more and more convinced that (normal) porn availability in fact reduces sexual assault.
I don't see an obvious reason why it should be different in case of CP, now that it can be generated.
I don't know why you would expect a pattern-recognition engine to generate pseudo-random seeds, but the reason OpenAI disliked the prompt is that it caused GPT to start repeating itself, and this might cause it to start printing training data verbatim.