One of the choices Apple made when designing the iPhone 5 was to limit the time the metal spent anodizing. This wasn't such a problem with the white iPhones, but very evident with the black phones. The anodization was only surface deep. You could scratch the phone with something and the bare metal beneath would show. Some people compensated by buying these gun industry paint markers that you use to fill in gaps on rifle barrels where the bluing has come off. I bought one myself, although the paint didn't stay on for long.
But even with all that, I never thought it justified blowing through ten phones!
However, the linked thread (and others like it at that time) were roughly at the tail end of a period on MacRumors where the iPhone was primarily considered to be a status symbol, rather than a tool a lot of us think it is now. So, yeah, some people were 'teaching Apple a lesson'. Can't have an 'imperfect' status symbol!
Shame all those brand new phones went back either as parts or replacement/refurbs. I had to take my own 5 back shortly after receiving it because it had a bad speaker. Then twice more because of swelling batteries. I'm on my fourth iPhone 5 now (it's not my primary).