He was a war criminal and a Nixon crony who among other things started the US practice of overthrowing democratically elected regimes to install US backed military juntas
Kissinger can take the blame for a great many things, but not for starting the US practice of overthrowing democratically elected regimes. He was still getting his Ph.D. when the CIA helped overthrow the Mossadegh government in Iran, primarily to help our buddies in England keep their hands on the Iranians' oil.
That piece of corrupt foreign policy has spoiled U.S.-Iran relations ever since, but Kissinger had nothing to do with it.
