Richard Sherman is NOT accepting the (not-really-an-apology) apology from the wife of Bills kicker Dan Carpenter ... calling it "ignorant" and bringing up the Ku Klux Klan.
Kaela Carpenter insisted her tweet calling Sherman an "animal" and threatening to castrate him was not intended to be racist ... and though she never specifically apologized, she tried to explain that it was just a joke.
Sherman responded on Wednesday afternoon ... and he wasn't laughing.
"It's not surprising at all," Sherman said. "This is a day and age, you've got the Ku Klux Klan running around.