Why is that the reason why? He clearly won the rematch. Losses shouldn't put a fighter down, especially if he has beaten the guy who beat him. Almost every great has lost to someone they shouldn't have. Ali lost to Norton Louis lost to Schmeling Pacquiao lost to Morales Charles lost to Marshall Robinson lost to LaMotta I can keep going but you get the point. One loss isn't a reason to not be a great, and Mayweather technically didn't even lose. There's loads more reasons why he isn't the goat
Did you even read my post? Once. He arguably lost once in his prime, and then whipped him in the rematch. All fighters lose. It's just what happens. And Mayweather didnt even lose