Bikes equal to this and above have been sold forever. This is just electric. The website clearly states for off road / consult local laws.
At 15 and younger I rode a Kawasaki 175 often... Off road...but admittedly sometimes on. Don't remember if it did 60mph but it was definitely more than enough bike to end things. At 15 there's organized competition @250cc
Oversight is the parents responsibility.
It's not necessarily a bad idea but education, supervision and the riders own sense of responsibility is key.
I think we can park some of the the high horses.
Now for those beers and that dime bag