That’s very common in tech. I knew of a guy that worked at a company that had contractors and full time, and wouldn’t let the contractors eat at the pot lunch with the others.
That was when I decided to never be a contractor at a temp company even if it pays more. You’re considered trash.
A programmer friend described how tech workers at many clients resented the contractors because they knew they were paid better and wouldn’t be forced to work weekends/holidays because it cost the client too much. Many of the tech workers at clients had stepped off the contractor track (took a job offer from a client) for some stability/benefits but in that industry it sort of froze your value/earnings (while the value of contractors continued climbing as long as they were always learning new programs and such).
As long as my friend was a programmer he never took a regular position with a client, and when he’d had enough he left the field altogether (to work with Americans again).