Let me throw this in there. While I agree its a millennial thing we were hardcore primitive campers until recently. We would camp five to ten days in a tent and have been doing so for years.
Our family has grown to 5 now, with that my kelty quatro was outgrown, then to a four season rei 6 something was outgrown. Now we went to a ten person Coleman that is huge. All of the sights around here are doing the same thing and putting in "pads" or like your place has "borders." Those things are a pain in the ass. The first problem is the retard who installed them. Poor grading, irregular shapes and layout, then fill with razor rock.
The sight is now tailored to camper campers and not tents. The prime sites get picked and people like us get stuck trying to fit a ten foot tent into an 8 foot pad.
Not justifying poor behavior but what I see more is lack of concern for others as a whole. There was a thread here a while back about allowing the use of your campers toilet while in a traffic jam. 90% of the replied was NO and Hell no's. I think the problem is both ways.
We moved into our trailer because campgrounds are tailored to be used by trailer campers. And there is some snobbery with the trailer users.
Like I said, it goes both ways. I am a gen x and have to deal with my parents as well as the millennials as well. Both are screwed up but it is our burden to bare.