Great article!  I believe through my experiences, work place bullying occurs when you have one boss in a position of authority who is unqualified to be in that position where they are expected to lead by example and they lack the qualified training and or intelligence to achieve any level of expected leadership abilities.  This problem can be compounded when you factor in office politics and favoritism where the same boss cannot separate work from friendship loyalties.  Then the problem flows down to the self entitled "friends" of the boss who hold a level of informal authority if for no other reason than because they are friends with the boss and have his ear.  Thus effectively paralyzing an organization, assassinating the character of anyone who stands up to them and ensuring their informal status and power continues to protect their personal interests rather than the interests of the organization.  This alone has cost organizations in the loss of good professional employees.