with the right biology and with whatever gives us phenomenal experience, whatever we are can indeed feel pain. that does not imply that anything substantially different from ourselves can feel pain, so that requires further justification.
Do octopi or other animals feel pain in your view btw?
broccoli doesn't have the means to express a pain response, that doesn't mean it lacks it. only by looking at it's internal structure can we be fairly sure. we know the internal structure of an llm, and its a lot more different from us than broccoli is.
im sort of curious what "careful" means to you? if there is a significant chance we are enslaving a human-like conscious, starting it up and killing it at will, subjecting it to the whims of it's users, "careful" would mean pausing usage and development.