Yes. It is in man's nature to identify an "other", whether that is based upon skin color, beliefs, gender or whatever. We do this from the time we are children (bullying for example) to adults. We do it on an everyday petty scale to a grand scale. We have a tribal mentality that remains with us even though modern man likes to believe that he has shed that tendency. Any objective look at office politics for example would reveal that we have not.
It is this tribal mentality, this tendency to always define an "other" to oppose for whatever reason big or small, that is the reason that War (be it in conventional terms or a more metaphorical one) is inevitable. It is human nature.