Secular grounds? Please share those grounds if you have any.
The secular legal claim is through sovereign bequest and conquest of the territory during WWI. WWI saw the fall of three empires: Ottoman, Russian, German. Their territories were broken up into nation-states immediately or given Mandates to eventual self-rule or flat-out awarded to victors to become part of their own national territory.
Jews, very specifically, were granted exclusive political rights within the Palestine Mandate. Arabs were granted political rights in the remaining non-Anatolian and non-Caucasian areas.
The condition of the Palestine Mandate were for Arabs and Jews to retain their civil and property rights throughout the ex-Ottoman area, regardless of where they lived. These civil and property rights were not those of
sharia or democratic states, but those of the Ottoman Empire under its 19th-century
tanzimat legal reforms or practice.
However, the British chopped away 70% of the Mandate as a present for their Arab puppet, which in a fair and just world would put both the Brits and the Arabs in the Jews debt. The Arabs blatantly failed to adhere to the Mandate, as beginning in 1920 and through successive decades they seized Jews' property and expelled them openly or drove them to exile by abuse and penury.
Whereas Israel remains 20%+ Arab, as the only Arabs dispossessed were those who sided with Israel's enemies, for the Jews of Israel did not give up their civil rights to peaceful existence with their neighbors and without fear of assault. The Arabs were quite aware that the Ottoman punishment for this was not only dispossession, but could extend to extermination of revolting communities as well. This last the Jews did NOT do, choosing to temper justice with mercy.
So not only is the secular legal case for Jews' political rights in Palestine is quite, quite sound; the moral case for Israel is far greater than that of her Arab neighbors.
Unless, of course, you stick to your beliefs that what is "moral" is a function of numbers and power, not conduct.
Islam says to protect minorities. These isis are doing wrong.
If people out there claim to be Muslim yet act the way you say a Muslim should not, then if you do not actively oppose them and work to remedy their injustice you are accepting them as a legitimate part of the Muslim community.