The obvious difference is that AI has abundant use-cases, while Crypto only has tenuous ones.
Maybe there is added negativity considering it is a technology where there is clearly a potential threat to jobs on a personal level (e.g. lift operators were very negative towards automatic lifts).
Most people will agree that LLMs are pretty neat, but now instead of every startup being "like Uber but for ..." they are "like chatGPT but for ...".
Everyone is trying to chuck AI into their products and most of the time there is no need, or the product is just a thin fine-tune over an existing LLM model that adds essentially near-zero value. HN is fairly negative on that sort of thing I think (rightly so IMO)