New Jersey is split up in to two areas..
Northern New Jersey, which is in the New York Metro Area and thus they accept the NYC teams as their own and Central/Southern NJ which tends to be Philadelphia sport territory.
And that is consistent with the media markets. North Jersey gets its news and entertainment primarily from the New York media and is considered part of the NY Metropolitan area.
South Jersey gets its from Philly as part of that metropolitan area.
Even the Giants and Jets, who play their home games in the Meadowlands (Secaucus) are called the NY Giants and the New York Jets.
And soon the NJ Nets (who began their NBA career in NJ playing their home games at the Rutgers University arena in New Brunswick) will be relocating to Brooklyn. At the end of their games, the Nets and their opponents were bussed to New York to shower.
The eleventh most populated state in the country, and it doesn't have a metropolitan area of its own. Newark? Trenton? Camden? Vineland?
Nope. It's a corridor without its own identity.