I don't really see this, atleast not on here. I think as a fan of boxing you cant admire one and not the other, because they both have the same character-qualities that make them loved fighters.
Fighters who were very good in their era, fought cleanly, ducked no one, gave good efforts, did not talk derogatory about their opponents after the fight, had no problems outside the ring, and stayed away from gambling / fix allegations. If the fighter died before his time, I think fans don't grind on him as much. I have not heard anyone trash Sal Sanchez.