> more terrifying than some trained and experience arbitrator with respectable work history, to me.

Roy Moore was a judge. Think of that. Ousted from the bench, twice, for defying court orders, ignoring the law, and displaying a lack of impartiality. This guys thinking was basically "I don't have to follow the rules, because God tells me what's right." And he was a judge for a number of years.

Now look at this video of a recent trump judicial nominee.

https://www.youtube.com/watch?v=c-zvNnFjk3Q

He couldn't even answer basic legal questions, and admits to have never tried a case in court. I believe he dropped out of the process. But others have gone on to be judges, with only slightly better credentials.

So having a judge decide is no guarantee of a fair outcome. Juries exist for a reason. They aren't perfect, and nothing ever will be.