Widebody
If a Chinese company started up in LGW next week with flying LGW to OSL whilst regulated in Jamaica with crews contracts from middle Africa I have no doubt that in my humble opinion every Pilot in the UK would be marching on the streets.
I am not sure that is the case. The EASA and local regulators such as UK CAA would check that all their safety requirements were being met (these are not driven by location of business). But apart from those safety/regulatory issues, I don't see any reasons to protest. Is it any different to regionals choosing which US right to work state they are based in? Their Ts&Cs are not too brilliant either.
Multinational companies have been making this type of choice of location of their HQ and business units for tax purposes for many decades. Provided all the safety regulations of the airspaces flown in are met, why is the multinational air carrier business different?