Every time I see this in the comments it's funny that they don't block me while connecting from country whose digital privacy laws are basically an even stronger version of the GDPR. Tells you about their true reasoning.
Personally I don't know about non-EU/UK countries with GDPR-style (or stronger) laws, so if I were operating a website that needed GDPR compliance (and decided to instead block visitors from the EU/UK), I probably would have no idea about needing to do something about visitors from your country.
So I expect their "true reasoning" is just ignorance.