They make a hero out of Rosh because he's fighting the Romans. He's a warrior, fighting for freedom, and his sort of action is physical. It's a kind of heroism they can understand, and one they can see themselves taking part in.
I do think they were right in making a hero of him…right, but limited. They paid him admiration because they understood him, and didn't pay as much attention to others they understood less (spiritual leaders).