I've been teaching undergrads for 3 years now, and while I try to avoid getting them to discuss things in an explicitly partisan framework, it's been pretty clear to me so far that the vast majority of them are either standard-issue liberal Democrats or moderates who are probably still figuring themselves out. I can't think of a single student who fits the stereotype of the alt-right Shapiro fanboy.
I've been working for a public school district for almost two years and, while there are a few alt-right troll types in the high school, they're vastly outnumbered and I get the exact same vibe from them that I got from my own "lol epic pedobear bacon longcat goatse" high school classmates in 2008, most of whom, a decade later, are generic late-Millennial progressives.
Most of the 'eternally 2016 essjaydubyoo cringe ownd rekt market place of ideas' content producers are far older than school age teens. Some are even older than me. From teachers I know, that stuff is really outdated and stale (oh look another anti-sjw vid) to kids or they've moved on. Stuff like Shapiro and Turning Point is simply a tool to make boomer Facebook drones think that young people agree with them. All the 'free thinkers' think the same, trot out the same arguments and go on each others shows. And besides if you make fun of high schoolers because they don't want to be shot at, they have trans friends and care about being 4 foot underwater and 40k in debt you're salting the ground.