A film glorifying him seems to be in bad taste (I didn't see it), but at the end of the day I do think there's some merit in the argument that soldiers set aside morality and ethics on the battlefield and just do what leaders tell them to do. Chris Kyle didn't start the war; he didn't invent the position of sniper, he just did what he was called on to do, and he was very effective at it.
Hasn't "I was only doing what I was told" been considered an illegitimate excuse for one's actions since Nuremberg?
Regardless of what he did or didn't do at war, his behavior off the battlefield was beneath the dignity of someone representing America's armed forces. He took what should be quiet, heroic public service and cheapened it into a commercialized, over-hyped way to make a quick buck off the same rubes who buy Lee Greenwood CDs and yellow ribbon magnets at gas stations.