Let me give it a shot:
In the 1970s, America supported the oppressive totalitarian secular regime of Reza Pahlavi, engendering hatred against America, the Western world and secularism in general, thereby creating a situation in which the strict religious fundamentalism of Ayatollah Ruhollah Khomeini could take over and impose its uncompromising worldview on the entire country.The same leftist logic applies to every country in the world. If a regime supported by America is in charge, everything bad that happens there is automatically America's fault. This position has a certain logic to it. Then again, if a regime opposed by America is in charge of a country, everything bad that happens there is also America's fault, since the bad thing ultimately results from a backlash against America, from poverty brought on by American pressure or some other bad thing America has done to the country.
Therefore, everything bad that has happened in Iran since then is automatically America's fault.
From the above, I think it's obvious that America is not the world's policeman. America is, rather, the world's husband.