Asking for the moderators to remove it is too much I doubt any admin is willing to go through zepher's account just to remove the feedback. Excluding him from DT is enough of a solution to this situation.
Since trust system isn't moderated by forum so it's not possible to remove any feedback's left by Zepher. Exclude him is only one solution but I don't think all DT1 will do it. Because some DT1 still believe on his judgment.