Head to the Rockies or out to Oregon if you want solitude hiking. When I hiked Mt. Bierdstadt in CO I was completely alone for 7 hours and never saw another person the entire day.
That being said, of course there are people like in this article, but they're only at the shelters that are close to town. Walk a bit away from the town, and you're golden.
Walking 15 miles into the woods to "party" is a huge ask. Shitty people are lazy.
The real story behind all of this is how young / homeless / disenfranchised people are turning to the trail as an outlet / support group. That is more interesting to me, and worthy of a story, rather than judgement as doom of the trail.
Its also just a really awesome trail (Montana/Wyoming/Colorado/New Mexico) with on a good year maybe 300 hikers starting(far fewer finishing or making significant progress)
Though it does take map and compass navigation as the trail is not complete and even when it is, there often isn't a trail just a line on a map.
The AT just seems anti-why I like to hike, and sounds more like a backpacking trip across Europe with your HS senior class.