Obviously his book was a serious treatise on war, peace, diplomacy and politics. Clearly he wanted to contribute something meaningful to the world, so he could change peoples perspectives and bring about a new era in soldier-civilian relations.
Or it was just Chris Kyle talking about why Chris Kyle was right to participate in the pointless invasion of another country, in which he killed 160 people, after repeatedly choosing to go back so he could pop more savages.
I dunno, you decide.