I think it's another example of "internet bubbles" - people with similar views tend to congregate together and this is particularly true on the internet, when going elsewhere is always just a mouse-click away.
When ChatGPT first launched, Lemmy was still pretty much a ghost town, and it did cause a lot of optimistic excitement e.g. on reddit. Lemmy got a big surge in numbers when reddit did its infamous API changes - enshittification driven by spez's and other reddit executives' insatiable lust to exploit the site for more and more money.
Perhaps for this reason, people on Lemmy are more averse to the enshittification trend and generally exploitive nature of large tech companies. I think this is what people on Lemmy object to - tech companies' concentration of power and profits by ripping off the general public - not so much the concept of LLMs themselves, but the fact they could easily be used to further inequality in society.
Yes you're right, sorry I went off on a tangent about the reasons for the intense negativity in the Lemmyverse about LLMs. I've been using lemmy for four years, and definitely don't think there has ever been any positive feelings towards LLMs here, especially as ChatGPT's arrival predates the first surge of users on Lemmy (and the subsequent appearance of all the instances we see today). On reddit, yes, and there are still many people there who still think OpenAI is great.