My point in clarifying that the Old Testament commanded the Israelites to exterminate specific barbarian nations was not to justify it by way of the reasoning behind those acts, but rather to point out that the edicts to destroy those enemy nations infesting the Promised Land were purely situational, rather than generally applying to all non-Israelites all over the world. The same cannot be said of Jihad, as Jihad is a general principle which has a much broader scope.