Did you call and talk to Duff? Or just post up here to bitch and bash. I really dont think that would take much to get it to work. Maybe they had a run of brackets cut wrong, maybe the arm was welded a little off, maybe one of the arms are too short or too long.... But holy cow, give Duff a call and let them know whats going on. Maybe its as easy as taking some measurements, and they would say that the arm is wrong or the bracket is wrong and they ship another one out. Who knows without asking
And dont think that we should be ok as a consumer with sub par parts, but just letting them know could go a long ways.
If it were me, I would have taken some pics, and measurements, fixed it myself, and installed it. Then called them to let them know of the issue, and shared the info so they have a chance to look into it. Not that big of deal.
I have had opportunity to meet the Duffs and tour their shop. Very good people, and I know they would not want a product like that.