the reason of the war is like why Judaism doesn't accept Muhammad (prophet of Islam) 14 century ago
it's because a lot of prophet from god (Allah) after Ibrahim (Abraham) is in Israelian lineage (lineage from Ibrahim -> Ishaq(Isaac)->Yaqub(Jacob) ... ->Isa/Jesus)
but the last prophet is not from Isaac lineage, but from Ismail(Ishmael) lineage, (later lineage of isaaq is called bani israel, and lineage of Ishmael is called bani adnan)
that is why i studied and what i believed, actually there is more reason, but this one is the most strong reason why they didn't accept Muhammad, some of people at Muhammad era in Arab accept Islam as religion from Allah, but refuse to worship Muhammad as the last prophet because of this.
i don't mean to abuse or discriminate... it's just this is what i studied, im sorry if someone feel assaulted, but i really don't have a bad meaning. I belive what i think is right, and so you are.(for some people religion is more assaulting than racist, me included :v)