Wars are horrible and they're almost always done for geopolitical power or resources, not to protect enlightened democracy or whatever.
Most US wars are fought because of realpolitics, resources, opening markets, company contracts, like a game of Civilization, empires battling empires, or plutocrats taking over markets in poorer parts of the world through brute force foreign policy, just like in the rest of history.
There is no US exceptionalism even though i love many things uniquely about your country as a whole and wouldn't live in neo USSR ( unless part of the intelligentsia, which in some parts look like parts of the american plutocracy ).