I'm a Clevelander.....so maybe I can shed a little light on why everybody's pissed at Lebron. Yes, he has the right to like any team he wants, but he should do so privately (most of us all agree on that). But it's like this: How would he feel if the Indians showed up at the Cavs' playoff games wearing Pistons shirts and caps? He would no doubt be angry that the team isn't supporting him.
The point is people aren't angry with LeBron because of his liking of the Yankees and the Cowboys, but because even though he's from the Akron/Cleveland area, he doesn't seem to care or realize how badly these people want a championship. Their star basketball player who's team just got swept at the NBA Finals shows up at a very important game, which could potentially get us closer to a championship, rooting against the home team is not something the people of Cleveland want to see, especially when he knows what it feels like to lose a chance for the championship. But maybe I'm kind of wrong.....the teams he did support like the Yankees, Cowboys, and Bulls are all champions, so maybe he doesn't know what it feels like. Still however, he should simply have the decency to say, "Yes, I like the Yankees, but I support our Indians and all other Cleveland teams 100% and hope they do well." When you start saying that you want our town's rivals to win, it's like a slap in the face to everyone who came to your games wanted you to win.
Anyways, when the basketball season rolls around and Lebron gets us into the playoffs again, us Cleveland fans will completely forget this incident and start riding LeBron's coat tails again and treating him like royalty. That's the way things work in this town.