Learn English – a word for someone who hates or intensely dislikes one person

I think the three best one-word descriptions of Holden Caulfield are "crazy" (his own word), pretentious (a literary critic's word), and idealistic (my word) or unrealistic (also my word). Everybody's somewhat of a phony (see Erving Goffman's The Presentation of Self in Everyday Life). Nobody likes extreme phonies. That makes "the personality trait of disliking 'Phony' people" a normal trait that deserves no special label.

"Conflict-averse" is the term we use for this in the human services professions.