There is literally no fathomable way Mayweather would beat SRL. It is a thing suggested merely by the new era of boxing fans who's main source of information is boxrec rather than watching full fights themselves.
He's better at pointscoring in the centre of the ring, better using his feet, will use his height and reach advantage well, bangs to the body, can actually FIGHT and take the 'boxing' away from the match where it suits him, brilliant at forcing you to the ropes (something that Mayweather is very susceptible to becoming victim of), better jab, better combination puncher, much bigger punch variety, better 'runner', brilliant power, also a high ring IQ, an excellent finisher in latter stages.
One fighter has wins over the best boxers of all time across the range of different styles i.e Duran, Hearns, Hagler (whilst they were both notably past prime), Benitez.
The other fighter has wins over Castillo (rematch), Corrales, Canelo, old and finished Pacman at 147. There are many levels that separate these fighters.