How was Maddy wrong about her father's reason for keeping her race a secret in the novel, The Weight of Blood?

Maddy believed that her father kept her race a secret because he was ashamed of her. Though this might have been part of the reason, the main reason is that he saw how people, especially his mother, treated Black people. He did not want Maddy treated poorly because of his decision to sleep with a Black woman, so he tried to pass her off as white.