Arab rhetoric towards Israel and Jews, then and to an extent now if you look at specifically anti-Israel political groups/states (obviously now there are Arabs who have accepted the existence of Israel) is very clear.
The stage for genocide was absolutely being set up, and most assuredly would have been attempted. As a rule the Holocaust is an exceptional case, and should generally not be used as an exemplar to measure "genocide." Basically, and I say this as someone of partial Jewish descent, that you don't get anywhere in studying genocide by comparing genocides other than the Holocaust, to the Holocaust. Not because it was "objectively the worst" or something like that, but simply because it's mechanics and context were unique enough that it is generally not analytically useful. It's difficult, and maybe pointless to argue about definitions of genocide in a case in which it genuinely just didn't end up happening in our timeline though, but whatever.
It seems likely that the Arabs would have massacred soldiers and civilians, perhaps not with industrial efficiency, but the Rwandan genocide's main tool was the machete. Nobody but an idiot or bad actor would argue that what happened in Rwanda wasn't a genocide. Using Bosnia as an example, to some (stupid) controversy from deniers like Chonsky, one can even primarily target military aged men and it still be genocide. Hell we have documents from Hitler which order significantly larger proportions of Jewish men to be eliminated first. If the Arabs just go about ""targeting the men"" it's still genocide.
Perhaps the British led Arab Legion, would protect civilians, but that's one military unit that can't be everywhere at once, or, as a matter of fact, many places at once.
Even if the western powers choose to intervene, it's too late, the war is over. They may step in and help with humanitarian relief but that's about it, and that's still a maybe. The perception at the time was that Israel was fighting for survival, and still nobody lifted a finger.