[Elsie]

The reason is because they aren’t Catholic and they feel some form of inferiority, so they pick on Mormons.

Is this an example of...

Assigning Motive??

[Porterville]

I think it is called an “asinine motive” but in psychology it is a form of transference.

From Wikipedia:

Transference is a phenomenon in psychology characterized by unconscious redirection of feelings for one person to another. One definition of transference is "the inappropriate repetition in the present of a relationship that was important in a person's childhood."

[1] Another definition is "the redirection of feelings and desires and esp. of those unconsciously retained from childhood toward a new object."

[2] Still another definition is "a reproduction of emotions relating to repressed experiences, esp. of childhood, and the substitution of another person . . . for the original object of the repressed impulses."

3] Transference was first described by Sigmund Freud, who acknowledged its importance for psychoanalysis for better understanding of the patient's feelings.