Merchan is what the judicial system ought not be. Videos of him could be used in law schools showing students how not to operate a courtroom.
All Federal Judges go in for training at what is called The Baby Judge’s School before being assigned cases. Part of the curriculum is designed to prepare them for highly publicized trials like this, with actors playing the role of difficult witnesses and argumentative counsel. Sure, there are a boatload of cranky, temperamental, and excentric Federal Judges and Magistrates, but you never see one as inept at courtroom decorum as this judge is.