The Jews did not settle in Palestine by invading the territory, they purchased lands instead as early as the end of the 19th Century. Frankly, I've never seen a colonial conquest made by purchasing land! It is true however that the Jews established their state in a land that was already occupied, but they had no choice, they were a landless people. This is why they tried to recover their sovereignty over Palestine. It's not just because they happened to own this land 2000 years ago, unlike what the anti-Israel propaganda says! This is also why it was necessary to divide the land, so that both peoples can have a state of their own. Nonetheless, even if Israel were a colonial state, it wouldn't change anything to its legitimacy. Nearly all countries in the world are the result of a colonial conquest and no one questions their right to exist.
from the article: Hostility toward Israel is the ruling classes' new anti-Semitism