The term public relations was actually an explicit rebranding of the term Propaganda after it started to develop a negative association in the public eye. Look up Edward Bernays, it's a fascinating bit of history that's not really talked about much.

http://theconversation.com/the-manipulation-of-the-american-...

If you're into documentaries, "The Century of the Self" covers this subject excellently: https://www.youtube.com/results?search_query=century+of+self

One of my favorite documentaries! It didn't just give me new knowledge, but re-framed the way I view & process future knowledge.

Which also happens to be his role at Twitter, never mind the clickbait "Executive" in the headline.

If they're on "our" side, we call them PR reps, yes.