The nonsense in all this is that transit passengers create just as much pollution as a joining passenger, but do not have this pernicious duty levied on them.
But the joining passenger is likely to be taking money out of the country....
Go tell it to the Chinese and Indians
While those countries might be producing large amounts of pollution, the amount produced per person is far lower than any average in Europe or N America.
The real problem is burning rainforest - that produces more CO2 each year than the whole of the USA - and also destroys its CO2 removal and O2 & water production.