He made many stupid mistakes and helping Khominie was one of them. Whether it was his Muslim brainwashing that he was incapable to get away from even having lived in the US or thinking anything to get rid of Shah, he was an idiot.
Regardless of whether Shah was good or bad, but Yazdi being the first one to support Khominie and going to Paris, shows what a stupid ignorant and brainwashed by Muhamad from Saudi Arabia's Islam he was.
It is unbeleivable how some Melli-Mazhabi still defending this guy with such statement like: later on Between Bazargan and Khomeini he choose Bazargan.