>> When a judge has made a terrible decision for dumb reasons, you appeal it

This is not how the legal system works. You need grounds for the Appeal - such as procedural - AND need to get another court to agree with your grounds AND be willing to have the case heard again. None of these are gimmes, and they all take time and money.

This definitely how the US system works. The core job of the appeal court is correct errors of law.

Your other criticisms are valid, such as time, money and there is definitely deference to lower court judges. But the recourse for a judge misunderstanding the law (for AI or any reason) is the appeal process.