It's understood that in personal correspondence everything stated is the opinion of the author. Both my fictional examples were written from a personal point of view.

The actual difference was that one expressed a personal preference without being offensive; the other called a vast group of people "ugly", which is offensive, and expressed incredulity that they even managed to find each other sexually attractive enough to reproduce (which is naive as well as offensive).

Racism is primarily subjective, so that's no excuse either. Rational justifications for racism are more often than not a posteriori justifications.