Just to detail, not to contradict, an AI (LLM or otherwise) would have to actually understand how one action is ok or not with each of those three rules.
Like, is agreeing with some human's delusions (which currently LLMs do) breaking the first rule for some of them, or just complying with the second? Is it still ok if it's encouraging them to take some harmful medicine or nutrition? (Like that guy was encouraged to switch to natrium bromide as a substitute for the salt he was told was harmful, resulting in very serious medical problems.) Or if it's giving up and encouraging them to go into a lawsuit that results in a massive loss AND negative PR? (Like the Krafton CEO was encouraged by ChatGPT.) Other people have ended their life over such massive losses, albeit when using their own money not corpo funds. Is it actually harming a human if you hack into some company's database for more info? Is it harming a human if you humour their AI psychosis, to the point of their becoming a recluse and isolating even from their spouse and parents, or just obeying the second law? Or to the extent where they don't get therapy for some trauma?
How's a poor LLM trained on Twitter and Reddit posts supposed to know for sure what applies to each edge case?
PLUS, the 3 laws are a gross oversimplification anyway. Reality is much more complicated. Kinda like when Moses thought that 10 rules, out of which only 5 have anything to do with interacting with other humans, are enough... and then it balloons to over 600 laws to actually cover everything.
But I mean, just to stick to concrete modern day stuff: should a military AI flag an enemy attack, even if it results in humans being killed in the fighting? Should an AI recognise the face of a murderer in a video, even if he could get a crappy jail experience for the rest of his life, or even death penalty? I mean, it IS causing harm to one more human. Or to finally take on the third law, is it OK to stomp on someone's beloved cat when it's rubbing against your legs and COULD trip you down a flight of stairs? That's not a human. The 3 laws have no bearing. Etc.
And basically that's why (regardless of LLM limitations) using fiction as evidence in an argument about RL is actually a point on the crackpot list.