I am not saying that war is humane in itself, of course not. But there is a reason we have developed weaponry which causes as little damage to civilian life as possible (even if it doesn't always work perfectly); there is a reason we aren't using our nukes to destroy half of the middle east. You could argue that this comes down to fearing repercussions from other countries; but the only reason these repercussions are a consideration is because we know that the deaths of millions upon millions of innocents could never be seen as excusable.
Saying 'war is inhumane' is a blanket statement and blanket statements are ALWAYS lazy. It's pretty clear that the humanity of warfare has developed significantly over the last century, among developed countries at least.