Why do people think US intervention is bad?

For the most part whenever we intervened in foreign wars, it was good. For example, if Japan had not bombed us, Hitler would have killed countless more people, and then he would have come after us to finish his anti-Semite campaign. Our intervention saved South Korea from communist rule. We liberated Kuwait from Iraq. So for people to say that whenever the US gets involved the situation goes terrible seems a little harsh doesnt it? I admit, we should let Libya and all the other Middle Eastern Countries deal with their problems, but just because we are intervening when we dont need to now, doesnt mean we never should have gotten involved in anything.