I am not sure if we know that Palestinians are native to this area, we have many things pointing otherwise. For example waves of migrations from Arabia after the arab conquest and soldiers being given land and settled there as reward.

Wikipedia is not the best of sources for this topic, but you can read more here https://en.wikipedia.org/wiki/Arab_migrations_to_the_Levant

Your perception of colonization is a bit anachronistic. Your understanding of what colonizing means is a bit different than what they had in mind, as evident by the difference of what Zionism means and what colonization means today.

Main differences are, no host country, no goal of economic exploitation, no goal of subjugating the locals and most importantly, as a means to return a people to its historical homeland by creating a national movement. This never happened anywhere else, which means colonization is a misnomer, decolonization in this case, if was not overloaded would be the closer term, but also non-exact