Earlier quoted context omitted.
NPC as in non-playable character? One of the first search results reads: «[…] slang used by millenials to denote people who act as if they are being told by someone to act in a specific manner, although that may not be the case. Using this abbreviation, the commentator or the creator is poking fun at the other person for acting in a certain manner.»
Right word, wrong meaning. In the result you quoted, a person's intelligence is being compared to that of a NPC, implying that the person can't think for themselves and does whatever they're told like how NPCs in games act. The gp seems to imply a slightly different meaning, where a person is thought of as being not being a real person, and is only someone you go to for transactional work related stuff.
https://www.npr.org/2011/03/29/134956180/criminals-see-their...