Well hackernews wont like this but the answer is because it's enforcing the status quo. Verifying age for age-related materials and services. Some internet related services had a defacto exemption from following the laws because the enforcement logistics just werent there. A physical store that sells porn has to ID whereas online you dont, for example.

In addition there are more services, such as social media, becoming age-gated.

The enforcement hurts the sensibilities of people like us on hackernews but it's common sense to a lot of people. We live in very polarizing times, but as you've noted, it has bipartisan support. The easiest explanation is the hackernews-friendly take of lack of enforcement mechanisms is the more radical one.

Personally I think it's a bit sad but inevitable. The laws are just catching up. And there will absolutely be some good coming from it, such as holding companies liable for breaking the law.