Does Vajrayana accept the idea that Buddha placed Lord Yama (a supposed Bodhisattva) in charge of the hell realms to ensure karmic retribution?
Yama is a known God of the lower realm in all forms of Buddhism, I am not knowledgeable about particularly Vajrayana, but I guess they do accept him, there is no reason why not, when he mentioned in all of the sutras
Yama is the God that humans meets when they die, because he rules Karma
I am not sure whats your issue with that
Hope this help