Is Coppola Commenting on War?

There has been one of many conflicts in The Godfather that I am commenting on.  When Michael kills Sollozzo and McClusky, he starts a war.  However, I believe that it started even earlier.  I think that the war started with the killing of Luca Brasi.  The Corlerone's then killed Bruno Tattalgia's son.  I think that public opinion is important and they retaliated not only to avenge a death, but to appear to the other families as strong.  To appear strong as well, the Tattaligia's killed Sonny.  Neither side wanted to seem weak so they retaliated by killing. This will eventually lead to war.

There was one line in the movie that makes me question Coppola.  Clemenza says "[p]robably all the other Families will line up against us. That's alright --this thing's gotta happen every five years or so -- ten years -- helps to get rid of the bad blood. Been ten years since the last one" (The Godfather Transcript). The quote makes the viewer think that Clemenza is all for war and that it has to happen eventually.  I think that Coppola is stating that no matter what happens, there will be wars.  This may be indirectly stating that humans are wired to be violent.