A significant part of the cultural value of the internet comes from free anonymous expression. As a key example, look at 4chan - anonymity taken to it's extreme has resulted in on one hand yes a lot of disgusting stuff, but also a cultural hotbed.

Age verification is de facto identity verification. Eff says it well:

> But no matter the method, every system demands users hand over sensitive and immutable personal information that links their offline identity to their online activity. https://www.eff.org/issues/age-verification

Tying every action taken online to the user's real identity will have a deep and catastrophic chilling effect, destroying those very places that are creating our culture.