Go to youtube and watch/listen to what Finicum says to the state patrol officers before he races off: he taunts them to shoot him (because he won't comply) and says he has reinforcements coming and a "bloodbath" will be on them. That's not a peaceful man, that's a guy who's nuts, refusing to comply with lawful commands from law enforcement, and threatening officers with harm. 
He's lucky his actions didn't cause serious injuries to those unthinking enough to have ridden with that nutcase.