I don't mind people liking the Yankees, but that's because most of my family has always liked them. Could never stand the Broncos and Cowboys fans while in New Mexico; they made the sea of Steelers and Raiders fans far more likeable.
I never understood people that flip flop between winning team, especially since I've been a Dolphins fan for the last two decades, the same that have been absolutely horrible. I think it will make winning, if and when it happens, that much more great. I know it was incredible for my Dad to see the Chiefs win after living through the fifty year drought. This last Super Bowl was tough for him, but I don't think he would trade many things for the one they won.
I get my sisters only liking a team based on a player since they're just girls who don't really care for football otherwise, but I would never do it. I would especially not do it for Lebron. Even with the Heat being one of my favorite NBA Teams, I actually rooted against them in those Finals with him. I will forever be for the team opposite of him in any of the Finals; I don't care for him at all. My love for the Heat came with Shaq & Wade, and it returned once Lebron left town. Butler & Dragic make watching the Heat just as fun as when I first enjoyed watching them. My devotion for the Suns is because Nash was on the team basically every year I was young. They never won the big one, but they had some great teams back then that were incredible to watch (they just could overtake the Lakers and Spurs, but not many did back then).