because nobody else thinks it is at all enforceable.
Nobody that's FAA thinks its enforcable but the rest of us do.
"Can I see your passport please"
"OK a EU one, where are you resident?"
"not in Europe"
"Can you prove that please"
And you will either be.
"If you look you will see I have a UAE (or take your pick of country outside the EU) residents work permit"
"thank you Sir safe flight"
Or
"err um, I am resident in the IOM"
"where do you pay tax?"
"well the UK" or for that matter any other country in the EU.
"right could you please come with us to the station you have the right... etc"
If you are dual nationality with a outside EU passport you may get away with it but I suspect you will eventually come unstuck when they start looking at visa's, then when you produce the EU passport they will get you.