From the filing:
"Defendant’s use of Forest Hills Stadium for commercial concerts violates the residential zoning applicable in Forest Hills Gardens. All stadiums in the City require a special permit from the New York City Planning Commission, which permit may only be issued in commercial and manufacturing districts for good reason—stadiums (particularly open air stadiums) are very disruptive uses and incompatible with residential communities. Any claim by Defendant to a “grandfathered” status is meritless due to many years when the stadium went unused and was allowed to deteriorate."
Read their court arguments here: