they dont care about where you stay and whats your other nationality when it comes to tax. in most cases you need to pay your tax. you are also a citizen of their country as long as you hold their passport.
I would like to correct some of your comments.
These two sentences are misleading,
// you're bounded with their country if you have their "passport"//.
Again,
//you are also a citizen of their country as long as you hold their "passport".//
Passport is just a travel document. There are lots of people (millions) haven't got a passport.
The word "passport" should be replaced with "citizen/citizenship".
Thanks.
