No, it isn't ignorant, it's history, and pointing to other historical examples of colonialism and imperialism doesn't make modern colonialist states legitimate. Romans lived in the UK over a thousand years ago, but that wouldn't give their descendants in modern Italians the right to occupy the UK, and us native Brits would be well within our right to fight back any invading and occupying force whether the invading and occupying force likes it or not. Muslims, Jews and Christians lived in relative peace in Palestine for almost a thousand years before the British put Israel there.