Even in the past, US was more of a gangster supporting its gang rather than a fair hearted policeman. Its support to Pakistan during Bangladesh (East Pakistan) genocide is well known.
https://en.wikipedia.org/wiki/Archer_Blood#The_Blood_Telegra...
That describes most nations or polities going back to prehistory. It's unfortunately not the part of America's power projection that is unique.
Or the Indonesian genocide. Or giving Pol Pot diplomatic cover as soon as they saw him as an enemy to Vietnam. Or couping essentially every country in Latin America.
The "policeman" narrative has always been propaganda.