Do many campgrounds discriminate against TC's...?

Not sure what you searched on but this subject comes up frequently. Yes there are RV parks that "discriminate" against truck campers.

Not "many" by any stretch of the imagination, though. A few, maybe some, but not "many."

If you come across one, just move on to the next campground. Good or bad, it's private enterprise at its finest. It's how someone wants to run their business, and how its run is none of your business.