By your logic, the only evidence in this article that they raped and beat the man is the word of a convicted felon. When a person pleads guilty to a crime we generally accept that guilty plea as the truth. No evidence has been offered to suggest that he wasn't telling the truth. I still say everybody wins.
You make no sense whatsoever. The rapist was convicted of rape, therefore he has been proven guilty to the satisfaction of a judge or jury. Just because somebody confesses to a crime, that does not mean every additional self-exculpatory statement they make need be believed. You should not talk of logic. You lack the ability to recognize it.