Avi K,
Non of those countries have ever indicated that they are willing to grant citizenship to 4 million Arabs from the middle east. I’m relatively sure non of them would ever do this. Probably half the world would love to be citizens of the rich Western European countries and Canada. It’s just not going to happen though, it’s simply not practical. The Palestinians were living in the lands the modern state of Israel now controls before 1948 from their point of view and the point of view of the countries you mention they belong in state there. Not in Europe and not in Canada