> Or to put it differently, The US cheese industry has strong protection from the EU cheese industry's naming rules.

I suppose. Anyway, this is like buying hamburger meat and discovering it's made out of ostrich.

I think there's a big difference between making it illegal to name something because it wasn't manufactured in a certain spot, versus making it illegal because it's a completely different product. I couldn't care less if Feta was made in Greece or not. But Feta from cow's milk isn't Feta, any more than a peanut butter sandwich made with hummus isn't a peanut butter sandwich.