Archeological study bears out that both Palestinian Jews and Palestinian Arabs have far more in common than apart, because as in most cases of conquest, the native population subsumes the conquering people not the other way around, both Jewish and Arab Palestinians are ethnic natives
The Arab conquest was as long ago as the conquest of the region by the Jews, give or take, so in pure calculus they have as good a claim, and the far more recent claim, than European or north African Jews, or even other levantine/near eastern Jewish populations
Even if they weren't, that does not give cause for conquest, any more than a Spaniard could claim ancestral right to southern Sweden as a goth, or an Englishman to Sicily as a norman you deeply silly person