Earlier quoted context omitted.
Seems like there's a sovereignty issue here. If you negotiate a deal with the highest authority in Ireland, and they sign off on it, are you done? Why do you have to care what other deals they have made with other parties? Or is nothing Ireland does binding, until someone else with real power has counter-signed it?
If you negotiate a deal with the highest authority in Ireland to access the entirety of the EU Single Market, then yes indeed you should care about EU laws. It's not like Apple is only selling iPhones in Ireland... If you sign a deal with Nevada to sell products in the entirety of the United States, you expect federal laws to apply, don't you? Well, EU is not a federation like the Unites States, but it's half-way the…
> hard to grasp for non-European. And to be fair, for most Europeans too
Yes, I think the degree to which this thing is a super-state (or at least claims to be one) not a trade club is not fully appreciated. Not least by the voters in whose name it was created. It's in some gray area between a federal state and a treaty, and cases like this are illuminating as to precisely what shade of gray.