KF is owned by a US entity and Joshua is not a citizen of any European country that we know of. He's just alleged to have lived there for a time.The first thing is that unless he was living in a European country not part of the EU, any EU member state would shut him down because Kiwi Farms violates GDPR. Things like doxing and posting archives of social media posts of various lolcows violates the EU's regulations in regards to online privacy (Right to be Forgotten). In other words, Kiwi Farms would've been shut down by the EU regulators a long time ago so if Jersh was living in Europe then I doubt he was living in a country that is an EU member state.
As such, the EU really doesn't have a leg to stand on with regards to KF violating it's laws. The most they could do is prosecute Joshua for his own speech if he were residing in a country who's laws allow them to.