We preach from such high and lofty positions sometimes, conveniently forgetting our own indiscretions.
But it's natural for humans to elevate their own righteousness at the expense of others. If it's natural for humans, then it must also be natural for nations consisting of humans. We love to compare ourselves against the worst of the worst sometimes. It makes us feel good about ourselves so we can go on justifying our behavior.
We can claim the high road all we want. But history tells a far different story of a nation that has (on occasion) needlessly stuck its nose into other worldly affairs and caused unspeakable tragedy and suffering. Being "less evil" doesn't mean evil doesn't exist.
It's good to be reminded sometimes that we too live in houses made of glass.