Den ekel- und haßerfüllten Kopf auf die Brust senken.
Letting the head that is filled with disgust and hate droop on the breast. [Kaiser/Wilkins]
To let one's hate- and disgust-filled head slump onto one's breast. [Hofmann]
It's unclear to me whether or not it would be legitimate to identify the head with thinking and the breast with the heart and therefore with feeling; I don't think so, because there is nothing essentially rational about hatred.
The image of the head sunk on the breast indicates submission, contrition, or exhaustion. The head is weighed down with a burden of hate and disgust, and to let it sink is to stop supporting it. Hate and disgust are a burden. Allowing the head to drop is not the same as banishing hate and disgust, but perhaps it is a necessary first step in that direction.