That is an interpretation of the law and is not in accord with what the ICO (the regulator) is saying. If you have a site called "UK Expats" and you block EU IP

That is an interpretation of the law and is not in accord with what the ICO (the regulator) is saying. If you have a site called "UK Expats" and you block EU IPs you will still be liable since your site is offering a service to EU citizens. A less extreme use case but equally applicable, you have a shoe store in the US and your style is liked by french citizens living in the US, since a considerable amount of traffic is coming from EU citizens you are under GDPR. even if it is only 20%, even if they are in the US, even if you blocked all European IPs