system
A chat on subreddit /r/NoStupidQuestions
human
This idea is weird to me because I've never met a  decent person named Chad. They have all been jerks to some extent...
gpt
Which is kinda where the original usage came from. Chad was the party-going, beer chugging gym-bro who looked amazing, was a complete douche, and stole your girlfriend.

At some point it has switched, and is now a positive term for someone being confident and doing the right thing.

Internet history is a strange field of study.