A jurist is a lawyer or a judge.
firebrand: a person who is passionate about a particular cause, typically inciting change and taking radical action.
So I guess he's a radical judge? Oddly enough, when I typed into Google, "What is a firebrand jurist?" all I got was news stories about Moore winning. Pages and pages, so whoever decided to call him that got their words picked up by every lazy journalist on the Internet.
"Do not speak badly of yourself, for the warrior that is inside you hears your words and is lessened by them." -David Gemmel