The land was purchased lawfully, but the owners from which the land was acquired weren't always resident on said land.
No country in the world operates on the anarcho-communist ideal of "use-own". The fact that the owners of the land did not live there really does not matter.
Oh, come now. This assumes that the people who sold the land actually owned it; that documents weren't forged; and so on and so forth.
I don't know enough about the situation in the region under Britain to comment but I am somewhat dubious that it's as clearcut as you make it out to be.
Now who's being emotional? Those poor Arabs, cheated at every turn, threatened to give up the whole of Palestine.
No, most of the initial settlement of Palestine was orderly and lawful. While there may have been some intimidation or corruption, it was far from being the norm.
It was purchased lawfully only because the British made expropriation of communal land lawful. There were some normal purchases of privately-held land from Arab absentee landlords, but that's not what is objectionable. That at least didn't destroy communities.
Gating the Commons should obviously be undone in England, and we should obviously restore the rights of all those Yorkshire men who left the Woolen Provinces behind. So, much of East Coast America gets those sheep-raising places now, right?
Communal property was, for the most part, either not legally recognized at all or gradually phased out over much of the modern world. It was actually needed to increase agricultural productivity.
Look at the Tragedy of the Commons.
An Arab government would have abolished communal property, as has happened to a degree all over the Middle east. In fact, many of them did just that (Communal property was being restricted and sold off under King Faisal.)
If I leave the keys to my car on the hood and someone steals it, I may be an idiot, but that doesn't change the fact that whomever stole it is a thief.
Besides which the Zionists did not limit themselves to land purchases, but employed terrorism and intimidation. Googke "Irgun" and "Lehi".
You're using two fringe groups that were later dissociated with the mainstream Zionists. But if anyone suggests that the Young Turks had genocidal tendencies or that the Ottomans had religious fanatics, you throw a fit.
The Irgun and Lehi were far from the norm in Zionism.