A controversial Coney Island principal has pulled the plug on patriotism. Her refusal to let students sing “God Bless the USA” at their graduation has sparked fireworks at a school filled with proud immigrants. Greta Hawkins, principal of PS 90, the Edna Cohen School, won’t allow kindergartners to belt out the beloved Lee Greenwood ballad, also known as “Proud to be an American,” at their moving-up ceremony. ...snip... She told the teachers to drop the song from the program. “We don’t want to offend other cultures,” they quoted her as explaining. ...snip... The DOE reprimanded her in 2010 after teachers...