You get to root for whomever you want to root for. That's just how it is. Just like you get to kiss whoemever you want to kiss, and marry whomever you want to marry.
We are sports fans, and we need to protect this important freedom, even when it is not convenient.
So what if LeBron James is from Ohio but likes the Yankees?
To me, his willingness to do the politically unpopular thing just makes him an even better fan. Unless it's part of some crazy, very long-termed scheme, there's pretty much no chance he is doing this to be politically correct.
What I'd be mad at is if he pretended that he was always a fan of the home team just to score some points with the public.