Because South Side soccer players are coming into the HS program from very strong youth soccer programs. Just like going into an IVY league school, the IVY isn't making them "smarter" they are coming in well prepared and smart to begin with. Go to towns that have zero youth lacrosse programs i.e.. West Hempstead, Malverne/East Rock. Valley Stream, their programs have been in existence at HS level for years, yet they barely win more than 2 games a year for decades. There are no youth lacrosse programs in those towns.
