I sense that my opinion on this will be unpopular. So be it.
For the purpose of this thread ignore the specific case and the your emotions behind it. This thread is not about Larry Nassar's case. Focus on the concept of the judge's actions, and know that other judges have done the same at times. Hence the question: Is it acceptable for a judge to gloat when sentencing?
As soon as I heard the judge start off with, "It is my privilege...", I cringed. Maybe it's just me, but judges, while human too, should be above emotional statements such as that. Again, maybe it's just me, but judges shouldn't revel in the harsh sentencing of anyone, even when it is justified. The crime and punishment should be a somber and regretful moment.
I get the prosecution being elated over the sentence. That's fine. I get the victims and their families being elated over the sentence. Makes total sense, and I would expect it. But I'm sorry, I think it is inappropriate and undignified for a judge to show such emotion like that.