This is not just about porn sites, this is about any site with 'adult' material. For example, if Reddit refused to strongly identify (via a credit-card check) UK users, it too would be banned according to these rules.
I'd like to see them try blocking Reddit. I know "accelerationism" is seldom a great idea, but I think it might actually wake people up.
Just for UK geolocated users? I dunno, it would be even more unpopular with the user base than the last round of cleanup. And it would cost them money.
I seem to recall some level of geoblocking for German users as well, so it's not as if it's unprecedented.
How is the internet used? By Adults, by a broad majority. And adults have been drawing penises and breasts on cave walls since the beginning.