If so, which crimes?
Ex-pats with Polish citizenships especially..... if they are considered to be an "undesirable" should lose their citizenship.
This would include public display of disrespect for Poland and it's citizens.
Showing any hatred towards Poland or Polish citizens.
Any undesirable motives for Poland.
Mocking elected officials and talking down about them.
In short, people you wouldn't want for your neighbor because of their uncivilized actions.