Unfortunately, since the end of WW2 while most of the world was in shambles, the US took on this role. We started with paying for the rebuilding of Europe with the Marshall plan, and began to police the world because there was nobody else to do it. In our quest to maintain stability, often times in many regions we have been responsible for propping up dictatorships because the alternative was worse. And when we helped to bring down dictatorships, we often end up with exactly what we were afraid of. Many times the result may have been the same with or without American influence. But the fact that we are involved behind the scenes as well as up front puts us in the middle of too many conflicts. Even when the intent is solid, it seems to often the result is not worth the price paid.
In my view, US foreign policy both from a military as well as a diplomatic perspective should be based only on US national interests and not "humanitarian" initiatives. Most of the humanitarian efforts are rewarded with disdain by such nations anyway. We have spent too many decades attempting to be the police, and it has afforded those who we have policed well, such as the South Koreans to live under our protection and our dime. It is high time for them to do that on their own dime. And the places in the world that are in chaos, we get the blame whether deserving or not. And we get stuck with the bill their as well.