On the contrary, this passage appears to be designed as a repudiation of identity between Jeremiah and any prophesying madmen, whether occasional ecstatic orators in the temple area or attached personnel.
When a religious madmanprophesies that the oldest brother of the Agwu family will be killed by one of his brothers and the prophecy eventually comes true, the family must come to grips with this tragedy and struggle toward healing and redemption.