1 The question implies that you are guilty by association. This is a common tactic used amongst people that live parasocial lives. These people require regular reminders of how to manage their lives. Thus the following is the ideal response.
2 "My opinions on Person X will stay between Person X and I. Whenever I have a question regarding Person X; I will ask Person X the question. If you have a question regarding Person X; then go ask Person X."
3 The preceeding response displays integrity as the refusal to divulge your opinion of the person in question; preserves both of your reputations. It also diverts the question by shifting the focus towards the integrity of the questioner.
4 The best method to convay a prescription is by describing the way in which you conduct yourself followed by an assertion of how one can mimic your previously stated conduct.
5 If your response is followed up by a tantrum from the questioner; then the best course of action is to dismiss them with the proceeding statement.
6 "It is clear that you are not capable of having a calm and cordial conversation. Go take a break and calm down."
7 This is likely to result in them becoming irate followed by immense support for you from spectators.