seems pretty simple but, to each their own. have as many team favorites as you want. seems many, like myself and including the OP are loyal to one team. good for us. likely most nfl or even college fans remain loyal to one team. even if they move as I have, remained a loyal bills fan.
I guess I can see why you question it, saying he's a loyal die hard fan to more than one team (loyal: giving or showing firm and constant support or allegiance to a person or institution > singular) but is there a limit to loyalty? I know you can't be loyal to two wives but were talking football teams. I don't know, until now I'd never questioned or thought about how loyal a fan of their team(s) they may be or judge their loyalty for that matter. that's on them, I know what nfl team I have been loyal to for over a half century now, that's all that really matters.