For reasons I won't dwell into I have some insecurity and trust issues, and regarding sex that means I won't have sex unless is with someone I absolutely trust which doesn't sound bad but it can feel bad and it can reach a negative extreme.
Applying Occam's razor and ignoring pedophile conspiracies my idea is that current parents of teens just want to spare their children from these negative extremes and let them be more sexually liberated, which 20 years ago it might even have been healthy but in the age of social media where teens seek validation from not just from others like any teen but from complete strangers can be extremely dangerous for their self-esteem and sexual independence.
And as you said the virtue shit is just another layer of objectification, is girl watchers club all over again with new judging scales
Just imagine a 12 year old on twitter going like:
"Hi, my name is Amy, I'm 12 but everyone who knows me says I look like 16"
and then Bob appears:
"Is great to have African American representation on twitter of early developed tweens since
of course African American girls develop a lot faster than white kids, wonder if she's Bi
would add a lot more value, keeping an eye on this

"