Who knows?
But the rationale is this. Would you stop people in Surrey, moving to Hereford? Or vice versa? Of course not, because its *all one country*.
The EU is *all one country*, in the minds of its protagonists...
And that's the point, it was never a common market, never a confederation of nations - it was an attempt to produce a political and economic *union*, by a bunch of communists, who modelled it on the Soviet Republic and didn't change gear when that fell to pieces.
It has been sold as an economic brotherhood of equals, but it's not. It's a united soviet socialist republic.
Without the tanks.
Yet.