What are good reasons for the United States Congress NOT to recognize the Armenian casualties as genocide?

the 1915-1918 armenian casualties are gonna be recognized as genocide tomorrow in congress... but i am not sure i understand the situation. i know that it wasn't advantageous for the US to recognize it as such because it always wanted to be in good graces with turkey because of its military advantages or something? somebody please explain why the US would choose not to recognize it as a genocide.... Turkish people don't believe it was a genocide either right? they said it was collateral or something? what are the social stigmas around this?