Very true for the most part, but fallacies CAN be appropriate for a judge writing their verdict:

Ad hominem, in example, while a logical fallacy, can in its most classical form be used as a form of soft evidence: "George Floyd has a medical and criminal history of disposing of drugs in lethal doses by consuming them if pulled over. His lawyer's arguments are moot." is an ad hominem, it doesn't address the current court debate, it doesn't talk about the actions done that night. But it is a form of soft evidence that a judge or jury may take into account as to the character and likelihood of certain events happening as a defense lawyer may present them. Even more loosely, "George was a criminal who robbed women at gunpoint" is even more clear ad hominem, and poisoning the well, but would be taken as weak evidence. On the opposite side, "Chauvin has a history of hurting suspects during arrests, the defense's arguments are spurious in light of this" means nothing, as well, just an ad hominem, but will also likely be used as weak evidence against him as to his actions that night.