All these arguments about how Floyd is P4P greater than any fighter he holds a win against solely because of that win, should remember that throughout history, several fighters still rank higher than the opponents who defeated them.
Hearns KO'd Duran, yet Duran is still regarded as the greater P4P fighter in the ATG rankings. Benitez holds a win over Duran, yet Duran is still considered greater in the P4P ATG rankings. Some other examples:
Joey Maxim defeated Ray Robinson, yet Robinson is still considered far greater on the P4P rankings.
Harry Greb is still ranked higher than Tiger Flowers on the P4P ATG list despite Flowers beating him in 2 out of 3 contests.
Jack Johnson is still ranked higher as a HW ATG than Willard, despite Willard KO'ing him.
Marvin Hart defeated Jack Johnson who were each very close in age and experience--Johnson is ranked higher as an ATG.
Sandy Saddler beat Willie Pep in 3 out of 4 contests, yet it is Pep who is ranked higher on the P4P ATG list. Sammy Angott gave Pep his first loss which was never avenged, Pep is still ranked higher as ATG.
There are countless examples, feel free to post them.
No one thinks Marvin Hart has a greater legacy than Johnson, despite his win over Johnson when they were each very close in age and experience. They certainly don't think Willard was a greater fighter than Johnson despite his KO win over Jack. Somehow they think Johnson's win over a 20 year old Langford makes him the greater of the two. Those same fans also seem to think Mayweather will go down as the greater fighter over Canelo and Pac (who were not at their best) because he holds a win over each of them.