Surely a lack of suitably qualified pilots in Europe allows for Pilots from elsewhere to be 'imported' same as anywhere else in the world for jobs that can't be filled, first look locally and then advertise internationally etc..
There should be no argument, There are currently 3 agencies AND WX trying to fill these positions, they are not looking in the US for the fun of it.. they are looking there because they cannot get European BAe146/AvroRJ pilots. Supply and demand, simple.
(Edited for spelling)