Just because another group of people don't subscribe to your particular beliefs about there being "one true <insert-divine-figure-here>" is not an excuse to wage war against them. Violence motivated by or questionably "justified" by religious/sectarian differences, or that fuelled by excessive/unchecked nationalistic "my thingy is bigger/better/stronger than yours" arrogance (which essentially boils down to the childish posturing by cliques of 5-star generals holed up in secretive underground bunkers who have to find a way to justify their multi-billion dollar budgets each year), and in the name of claiming and grabbing territory that was "rightfully" theirs, has no justifiable place in the world. None. Zilch. Nada.
It's especially despicable when civilians and other innocent bystanders inevitably get caught up in the crossfire. Whatever your original motivations, when innocents are harmed/killed/maimed/forcibly displaced or imprisoned in the fog of war, regardless of which side is responsible, both sides are in the wrong. No single side can claim that they still have any semblance of a moral highground for any of the actions which follow. War is War. War != Good + Justified.
EDIT: Today's Google Doodle has a nice take on this