Kids don't go through the hoops to buy and install a VPN just to access porn. If they were not exposed to it in the first place, which is very easy without a VPN, then they wont have the interest to get one.
These were "normie" kids, not future hackers.
I just remembered my home IP address by heart to RDP back home. Another one of us hosted a free website somewhere with a spare copy of Ultrasurf to get around the filters in the first place.
When I hosted a Minecraft server, I routinely got DDoS'd by gradeschoolers. I have little doubt they could be tunneling thru a VPN in short order - because they did that too.
If someone made a list of all the things kids are willing to do just to access porn, it would blow your mind.