All nations within the Anglosphere (US, UK, CA, AU & NZ) have JD imposed towards citizens. I know that the US & Canada both inherited that from Britain, which explains why they have it. However, should it be entirely only the judge making the conviction (some countries operate on a lay-judge system meaning juries aren’t used, such as Finland or Japan for example) rather than leaving that decision up to jurors?
“Are meant to” and “supposedly” but unless there’s a mechanism to hold them accountable those are just wishful thinking. And at a certain point you run into “who watches the watchman?” I don’t have confidence in a jury to put aside bigotry but I don’t have confidence in a judge to either.