According to the arrest warrant, apparently the judge did talk to them in the hallway, rather than the courtroom. So, I recollected that wrong.
Nonetheless, the point stands that judges, and probably mostly the Chief Judge, are entitled to set rules or protocols for things like arrests occurring on courtroom floors, while the presiding judge of a courtroom is pretty much entitled to exclude offices or forbid arrests in a courtroom.
She could simply say, "I don't want arrests occurring in my courtroom, and probably not even on my floor, but that's ultimately the Chief Judge's call, not mine, so that's why I sent them to the Chief Judge." And the "cops" would probably admit that they are often deferential to courthouse staff, courtroom personnel, and judges on such matters.
But, it's not directly relevant to the offense, except maybe as proof of an overall intention to interfere with the arrest.
Possibly the most telling part of the prosecution is that this is a misdemeanor offense. And there's probably some DOJ guidelines on prosecuting judges and a judge might well have official immunity for courtroom decisions and actions, just like they have absolute immunity for deliberative judicial actions.