Porn sites don't have any interest in keeping this law either. Nobody with a functioning brain thinks you should have to upload your government ID to a website to browse content, no matter what that content is.
The situation is the opposite for age verification laws. In this case, both porn sites and their customers have aligned interests. Both sides want to allow VPNs. Both sides want to abolish age verification laws, and if that is not possible, to circumvent them.