This is why it's very different from many other conflicts: in Ukraine, for instance, you could potentially partition the land since you have a rather clear line dividing east and west over language and political views. Same in (South) Sudan for instance where you could separate majority Muslim populations from majority Christian ones. Not so much in Palestine, at least if you go back to 1946 before there were large population transfers.
If you look at population statistics from that era, you find that Palestinians outnumbered Jews virtually everywhere. If you had had a free and fair referendum and assuming that people would have voted along ethnic lines (why would Jews vote against having their own state, why would Palestinians decide that they wanted to be ruled by Jews), the Jewish state would have been the Jaffa region, period. And that's a huge problem. The right to self-determination is not only for white people, even though it took Western countries close to 20 years to finally realize that. The Jewish people certainly had the right to go to Palestine, purchase land following willing-buyer-willing-seller principles and perhaps one day become a majority there. I believe in open borders, so I have no problem with that. What I do have a problem with is when people claim that the fact that their ancestors may or may not have been forced to leave that area 2000 years ago means that they now have a right to exclude people who are currently living there. We all have roots somewhere in modern-day Kenya, that doesn't mean it's now okay for me to go and colonize that place. There's been invasions, etc. for thousands of years everywhere on earth and we don't go back 2000 or 3000 years to see who *really* has a claim on the land.