Black Americans have been taught, consciously and subconsciously, not to correct White Americans (as a whole). Not to generalize one White American, for all White Americans. But Non-Black Americans have been taught (consciously and subconsciously) to do the exact opposite when it comes to Black Americans.
A criticism of Black Americans as a group is to be looked at as one trying to help that community. However, if a Black American tries to group together White Americans for a negative outlook, it is traditionally defined as anger. This is further perpetrated by media outlets that will flatly ask in past years things like, 'Why don't Black people vote,' but never questioned why the voting numbers of White Americans were the worst in American history during President Obama's two elections.
It's not a double standard.
It's a standard that doubles our ignorance as Americans.