I agree. If we have to have age verification laws I'd rather they be applied to social media networks over some size than to porn sites.
That said, I think requiring ID is generally a bad idea regardless. Much better would be some standardized way for websites to tag the type of content in a header coupled with third party filtering solutions that could be applied at the network (ie firewall) or device level.
We already have standards:
PICS https://en.wikipedia.org/wiki/Platform_for_Internet_Content_...
POWDER https://en.wikipedia.org/wiki/Protocol_for_Web_Description_R...
ASACP/RTA https://en.wikipedia.org/wiki/Association_of_Sites_Advocatin...
What seem to lack is the will power to use them. Or after seeing in the linked site:
they really want mass surveillance for the plebs even by creating a weak point for enemies. To hell not just with rights but also defence. So any excuse will do.