Funny you say that, the entire reason I even opened my mouth was because I used to be on those contractor teams early in my career. Experienced it first hand. It sucked. I knew how much it sucked. I promised to be a better leader than the ones I had and saw.
It's a glaringly obvious caste system. I hardly see the difference between being punished for praising a contractor and being shunned for associating with an "untouchable".