No, McCoy was better win than Mitchell without any doubts. We don't have enough evidence to call this a robbery.
I'd say it's very open to debate. You could easilly make the case for McCoy, Choynski, and McCaffrey too
I don't Choynski was a 20 years old novice ,McCaffrey was a middle/ super middleweight who hadn't fought for 2 years ,and had lost his last fight to a 154lbs man.
Mitchell hadn't fought for nearly as long. McCaffrey was bigger than Mitchell, and had fought at a decent level more recently. And as 70's said, Choynski was an experienced amateur. He'd fought in multiple finish fights before facing Corbett, and was an amateaur champion.
McCaffrey was 5'8 1/2" or 5'9" and a middle weight 160/168lbs who fought heavies. Now do you want to argue about that? Can we now see evidence of these multiple finish fights? And which amateur championships did Choynski win?
Sullivan and Killrain yes. Mitchell no! McCaffrey and McCoy would be much better calls than Mitchell!
McCaffrey had not fought for 2 years and in his previous fight was beaten by154lbs Jack Dempsey. McCaffrey's record is 15-6-2 8 of his victims have no record at all and are listed as debutees. 6 of the others are as follows 0-1-0 0-1-0 1-2-0 2-1-1 0-3-0 1-0-0 He has 3 draws, 2 are as follows 1-1-3 1-1-0 Impressive!