I think it's difficult from our perspective to grasp just how divisive Rutherford was. The Bible Students who left the organisation because of the radical changes he enforced were branded as 'The Evil slave Class'.
I remember old JWs back in the 70s reminiscing about how traumatic it all was. Occasionally I would meet elderly people when going door-to-door who had left the religion in that period. Of course some groups who follow Russell still exist.