Its an excuse to hire Scandinavians.
There are more than enough unemployed locals they have no need to look outside.
The Swedish pilots union is very powerful and it is very Swedish pilots for Swedish jobs.
Realistically the only thing that matters is English because there are 4 lingos and finnish is acceptable but completely incomprehensible to the other country's.
The language is not a barrier as I know a Yugoslavian refugee that flys for them and his Swedish is very good but not native. But he holds a Swedish passport.
Go for it though and apply the worst thing that can happen is they say no thanks but don't get your hopes up to much.
It is not the same as applying to BA who if you hold the right to work in the EU will have no problems with what passport you hold and neither will the union.