Sorry, but Pinochet didn't "seize power with American help" any more than "the CIA murdered Diem."

The US was glad that Allende was gone and did nothing to remove Pinochet once he was in control, but the US did not put him there. Ambitious tyrants like Pinochet are capable of launching their own successful coups - as did Col. Gaddafi. As far as the US was concerned, once he was in power, Pinochet was the lesser evil compared to the possibility of a powerful Cuban-Soviet influence on Chile at just the time the US had been forced from Vietnam. The former KGB archivist Vasili Mitrokhin has written that Allende was in fact on the KGB payroll. See C. M. Andrew & V. Mitrokhin, "The World was Going Our Way" (N.Y.: Simon & Schuster, 2005), p. 80ff.

International politics makes strange bedfellows. But the Cold War's over, and it's time to give up the propaganda myths.