I don't think that ignoring it will make it go away or stop it from escalating. The jump from posturing extremism to acting upon extremist influences is very slight. By calling for investigation, those responsible are identified, and can be monitored and avoided by those they would target. Symbolic propaganda can turn into a rallying cry for target recruitment individuals...a swastika appears, and some poor dumb college student feeling victimized seeks out the group and becomes one of their brainwashed lackeys.
And for reference, here is a map of the monitored hate groups in NY and areas, provided by the Southern Poverty Law Center.
http://www.splcenter.org/intel/map/hate.jsp?S=NY&m=3
http://www.splcenter.org/intel/map/hate.jsp?S=NJ&m=3 (WOW jersey...)