Why is the world so hypocritical to the U.S. military operations?

It always seems like when we first get into an operation, we are supported at first, then called power hungry, with a bunch of conspiracy. But if we DON'T do something, we are criticized for not protecting people with our great military. Libya comes to mind, iraq, and even afghanistan. A lot of countries come to our defense, then when things get a little heavy they back off and call us bad, like seriously, what do you want the U.S. do, let people die, or stop the bad guys and protect the world?