I was heavily into football. And never once heard anyone talk about an ATG list. Sure you get people talking about goats and top five in each position. But not a 100 deep list of players.
By who's logic? I don't recall anyone saying he shouldn't be an ATG due to his losses? Which poster do you have in mind?
"Top Ten QB's" is discussed and listed frequently. "All Time Starting Five" "Best Righty and Lefty Pitchers" "Top Ten Male Players" "Best Seasons" Etc. Boxing is more unique than most sports for obvious reasons from age to global to no schedule. More for debate than most sports, really. But debating ATG status of boxers is the same as debating any sport and their athletes.