Think of it. A “civil war” is eminent, being pushed by a radical leader to boil and explode. He knows that a good portion of his army will split, and that the most dangerous among them, a sharpshooter, someone who could take out this said radical leader. Would it not be in his best interest to take the sharpshooter down before the civil war broke out?
Does he think that's the only sharpshooter in the country?
Not to belittle Kyle's accomplishments and general lethality as a sniper, but there are a LOT of SpecOps guys in the military, and there are FAR more very well-trained, highly experienced Soldiers, Sailors, Airmen, and Marines who would be a tremendous thorn in the side of such an agenda.
That's why I don't buy into the conspiracy theory stuff, particularly when it comes to "offing" individual service members. While the death is tragic and a complete waste, the net effect of neutralizing the overall threat against the statists is negligible.