The Jews are "Palestinians" too you know. There has have been a continuous Jewish presence there since, er, Biblical times. It's where they originated. But of course you know that, and are being disingenuous when you talk of them as only recent arrivals. They are the "de-facto indigenous people of the region".
The Jews that migrated to Palestine before world war two did so mostly legally. They didn't invade or misappropriate or trick the land from the incumbents (unlike say, the European settlers in the Americas). Sometimes they paid over the odds for marginal land that the current owners had no use for.
You state that "The Palestinians never migrated anywhere" but there has been Arab migration to the area now called Israel since the seventh century.