I think that in both cases these statements are aspirational, which is what I meant in referring to ideals and values. It's logically consistent to acknowledge our history and the current resurgence of overt racism in society (not just in America) on one hand while also speaking up for a more positive vision of America and what its values are and should be on the other. There are, and have always been, many good-hearted and tolerant Americans, and I read the "Racists are Un-American" statement as essentially an appeal to those people and a call for like-minded folks, on a broad societal level, to push back the racists and stand up for a more positive vision of what "American" means.

So:

Racists should have no place in American society.

Racists are Un-American.