This is a really good article which makes a lot of sense but I disagree that using 360 Degree Feedback should be used to directly identify bullying supervisors and managers. The 360 may very well become the nightmare tool that people fear because it's associated with problem behaviours rather than positive ones!
Therefore we would recommend evaluating good supervisor behaviours through 360 Degree Feedback, like helping and supporting your team, giving them work that develops their skills, and giving them regular and constructive feedback.
Bullying behaviours are so toxic that it needs more than an anonymous, development-based tool like 360 to deal with them. As you have said, clearly defining bullying behaviours, giving staff a confidential help-line if they need it, and demoting or firing people who bully others, are the best way to stop bullying in the workplace.