Palestinians are native to the area, they were not "brought in". This is something that is well known and established except among the deniers of history.
[1] https://imgur.com/a/BlTdfKy [2] https://www.youtube.com/watch?v=9Bmm_We6xDU [3] https://www.youtube.com/watch?v=jVMcqNOqdek
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
What happened is that europe continued their colonization and used what Germanhy did to the jews as yet another excuse to push the jews out of europe. They're the antisesmites: https://www.youtube.com/watch?v=u92CEAZjCOo
Also, the Hebron community that was massacred and ethnically cleansed in 1929 predated both Zionism and the Arab colonization which brought most Palestinians to the area
Also right after being against attacking civilians, you are saying that's actually alright because they had had done that as a reaction. That logic applies to anything in the conflict, including the civilian dead the Palestinians are now suffering after the massacre/kidnapping they have conducted. That's why I think you should rethink that line of thinking