Unconscious biases?

I work with a teacher who will only negatively mention the school from which a student transferred if it is a parochial school.

"So and so can't do such and such and so and so transferred from X Christian School."

 The school is never mentioned if it is one of the other public schools in the county.

Another teacher only mentions politicians if he has a particular dislike for them (and always from a particular party), even if other politicians (on the other side of the political aisle) are doing the same thing.

Just finished reading a book on mathematical innumeracy, written in the late 80s, in which President Reagan is mentioned four times negatively (five if you count one joke about the President's 1980 victory which was quoted from another mathematician).

I wonder if these people even know they are doing it.  Do they make negative comments because in their minds the negative consequence is associated with something they dislike?

I wonder if I do the same thing, without realizing it?

Or maybe I only notice them doing it because my biases are different.