Not sure why you're getting down voted. Porn can absolutely become a behavioral addiction.
I used to work at a place where we had a lobby guard that watched porn on his phone all day (sound off). Not sitting there trying to jerk it, it was a compulsion. He would just be watching it while talking to other people, standing by the door...it was weird. He eventually got fired because he genuinely couldn't not watch porn.
That being said, I'm a huge privacy advocate, and while there are actually ways to anonymously be on a website and verify age, that's not how anyone is doing it. Things like signing up for an account on a site and scanning your ID are just abysmally stupid. There's a zero percent chance that this system as is doesnt lead to data theft and possibly even extortion.
Tokenization is the easy solution.
You go onto you state gov website and get a token that just says "this is an adult." Nothing else. Token lasts 10 minutes.
Cut and paste into the site. They authenticate without saying who theu are, back to the gov site, "yo, this legit?" State says "looks like something we would do." State keeps no records of WHO validated the token, just that it was a legit token.
Same way that routers connect to VPN services.