Please show one example of an arab question the right of the jews to exist as a people. and yes the question the right for a jewish state in lands that haven't had a legal jewish majority in 2000 years but general land ownership they aren't against.I don't even see why genetics should be an issue here in the first place, which is why I don't even bother bringing it up in conversation. A disputed piece of land is conquered by various ethnicities over a period of many centuries. Eventually it falls into the hands of Turkey, and then finally to Britain after Turkey's ill-advised decision to enter WWI. Britain promises to divide the land between Jews and Jordanians, and both sides agree to it (circa 1920). Jews, having an unbroken cultural connection to the land spanning thousands of years, never having given up any claims on it in the first place, find themselves in the middle of a massacre with nowhere else to go, and end up migrating onto lands available for reclamation and usage.
Ever since then, the Arabs have done more than just question the legitimacy of Israel's current borders- they've questioned the Jewish people's very right to have any sort of lands of their own in the region, on top of questioning their very right to exist as a people. The more this kind of hardline threat to Israelis continues, the more it drives Israelis to respond in a similar fashion when Arabs are on the receiving end of the oppression. That's why you have cases like this, where it may or may not have been a case of racist discrimination, but you have the Arabs suspecting racism because that's been their past experience.