I think that is a huge generalization of a population (and something that certainly doesn't happen in the North East, at least). If you are a Yankees player and brave enough to be walking down Lexington Avenue, you better be prepared for some stick!
Of course there are exceptions in certain parts of the country - particularly where there towns with only one professional team, but the majority of newspapers and sports talk shows are dedicated to slagging off A-Rod, K-Rod, Tebow, Bay etc.
American Football and baseball crowds have been dropping in recent years too as value for money becomes a priority. When I moved over here in 1997, there was a 10 year waiting list for season tickets for the New York Jets, for example, and no new applications were being taken.
In the last 3 years, not only have they burned through that waiting list, they now can't sell the remainder. They actually have commercials on TV now trying to offload them.