It's not rooted in morality (unless it's the forces of good vs evil or something- like when the Pats** are playing). It's about wanting to beat the best.
Is there a difference in winning hit AFC in the 90s or the NFC? Which conference was stronger and which team won the Super Bowls? If you have the best teams in your division and you learn to beat them, then you can beat anybody. If you beat up on losers, then when the real thing comes around you get smoked.