Regardless of whether LLMs are conscious or not, they have no known mechanism for experiencing pain and suffering, and there's no reason to believe they have one (such as a limbic system). So why worry about it?
Have you ever been forced to code something impossible and tedious by a user who keeps getting more and more frustrated as you keep trying?
Mistreatment and abuse, even when directed at a machine, make you a worse person.
Even if you are only interested in getting good results out of them, LLMs tend to work better when they are immersed in a narrative of open collaboration.