Greta Hawkins, a principal at PS 90 in Brooklyn, New York, is receiving racist hate mail after banning the Lee Greenwood song "God Bless The USA" -- also known as "Proud to Be An American" -- from a kindergarten graduation ceremony, the New York Daily News reports.

“You are a filthy, dirty, ugly subhuman gorilla,” reads one of the letters, according to the paper.

The New York Post reports five classes at the elementary school spent months learning the patriotic song in anticipation of performing it at the ceremony, but Hawkins canceled the performance at a recent rehearsal, allegedly saying she didn't want to "offend other cultures."

Department of Education spokeswoman Jessica Scaperotti told the Post the song was scrapped from the performance because the lyrics were deemed inappropriate for the kindergartners.

But Hawkins, a Jehovah’s Witness who refrains from reciting the Pledge of Allegiance due to her religion, will allow the Justin Bieber song "Baby" to be performed at the June 20 commencement, CBS New York reports.

Parents responded by telling the station they believed the patriotic tune should be allowed, especially if the teenage love song is considered appropriate.

An excerpt from 'Baby' by Justin Bieber:

Are we an item? Girl, quit playin'/ "We're just friends," what are you sayin'?/ Said "there's another," and looked right in my eyes/ My first love broke my heart for the first time

Despite the outrage, district Chancellor Dennis Walcott told CBS New York he stands behind Hawkins' decision.