The equivalent would be geo-blocking the UK, and then someone from the UK travelling to the US to view your site to work around the restriction.

You have a level of plausible deniability there.

I think "UK citizen" should have been replaced by "person acting from within the UK". This is how it is defined in the context of GDPR - the nationality doesn't matter, what matters is where you are when you are provided services.

This seems to apply to persons acting from geoblocked UK/EU through VPN as well, which makes no sense at all.