Responding to the retaliatory feedback is no required because when you see a -ve trust on user X profile by user Y then you also check user Y trust to find whether you should consider user Y rating or not. You will immediately understand it retaliatory feedback on user X profile.
It would be more convenient to see at once the trust ratings of the members which left feedbacks.
It had been said that this feature was used before, but then was cancelled due to technical reasons.