system
A chat on subreddit /r/NoStupidQuestions
human
It's not rude but it is casual, she is asking you to accord her more respect and offended by the implication you're on common ground. 

It's silly.
gpt
Still remember preschool teachers saying, "Hey (sic) is for horses!" whenever we used it to address someone.

They didn't tell us they weren't our friends though. Maybe that's just OP's teacher's way of explaining the usage, but the way OP described it makes it sound a bit defensive of "status."