He is correct that palastine did not exist pre 1948, but that is irrelevant. Nationalism can emerge whenever it wants to. Zionism is just as made up as palastinian nationalism, so to defend one but criticise the other is dumb.
The difference between the colonisation of america and of palastine is that the Americans actually wiped out most if the indians so that they never became a serious problem in the future. The settling jews never wiped out the palastinians sufficiently enough to avoid future blow back.