Finder of fact could rationally have decided that a request for a case to be assigned to another judge, and that contained a threat against that first judge was in fact addressed to the first judge even though the note was addressed to the courthouse.
Although the jury instruction didn't adequately convey the element of subjective intent to threaten, the error was harmless, since the deft's only argument against subjective intent was that the note had not been addressed to the judge, and the note, read plainly, was a true threat.
https://cdn.ca9.uscourts.gov/datastore/opinions/2021/08/13/20-30019.pdf