Did the Arabs ever have it? Prior to 1917, for centuries, the Turks had it. Although Turks and Arabs are both Moslems, they sure don't tend to like each other. By the way, Turkish rulers spent a lot of their time in Palestine protecting the Jews from local Arabs who would from time to time massacre Jews. Although, during the last few decades of Turkish rule, Palestine's Jews finally began to arise from centuries of lethargy and arm themselves for self-defense.
The people who took Palestine from the Turks, not the Arabs, at the point of a gun, were the British, in 1917. Then the U.N. divided Palestine in 1947 between mostly Jewish areas, which were supposed to go to Israel, and mostly Arab areas, which were supposed to go to the Arabs. Palestine's Arabs have never accepted this concept, leading to everything which has happenned since then.
In any case, as I've said beforee, if the argument is "we're reclaiming land that was wrongfully taken from us", that's fine, we can discuss that issue - however that's very different from the gist of this article which is basically saying that Palestine was vacant, unclaimed and freely available for Jewish settlement.