The colonizers sought to impose an objectively unfair partition plan (granting them far more valuable territory and resources in proportion to their population at the time), with the muscular support of their European friends.
The Palestinians rejected this "proposal" outright of course, exactly as any self-respecting people would. Exactly as the Algerians rejected France's proposed "partition" of their historic homeland, and the Vietnamese (by and large) rejected America's proposed carve-out of theirs, etc (just to pick a few notable exactly from approximately the same time frame).
And yes, they made some poor choices of friends (as they readily acknowledge), and woefully miscalculated their own strengths and capabilities and so on. And then there are other factors you're carefully not mentioning, such as the expulsions and massacres already underway in Jaffa, Deir-Yassin and elsewhere before this supposedly entirely unprovoked and one-sided "attack".
But there's no reason to keep punishing the current population for these decisions, and exploiting this history (and the continuing indifference of both their so-called friends in the Arab world and the international community at large) for the sake of current and future land gains. Which is basically what the continuing (having of course never really ended) Nakba (that certain very notable public figures are proudly and openly hoping to officially upgrade to Nakba 2.0, in their own words -- do we need to name any names here?) is really about.
And whatever is happening in the ground today (and however much blame can justly attributed to both sides) -- there's nothing to be gained from nullifying history, or reducing it to such trite oversimplifications as in the parent comment.