If a majority of the Americans believed America was not generally the "good guys" it would be a sign of a failed democracy.

Similarly normal for the population of any country that has net negative externalities from America to view them as the "bad guys".

The current and growing anti-US sentiment is an expected result of an increasing gap between the US and the rest of the first world on economy and defense. The existence of a superpower is precluded on being viewed negatively by the rest of the world

> If a majority of the Americans believed America was not generally the "good guys" it would be a sign of a failed democracy.

No, it would be a sign of critical thinking and self reflection.