I used to go to a lot of Celtics games back in the days that the Knicks were not only relevant but in fact very good. Everyone at the stinky old Garden would boo the Knicks as loud as possible during introductions.
But we all knew that Walt Frazier, Willis Reed, Earl Monroe, etc. were very good players and worthy of our respect.
Phil Jackson, not so much!
A great opponent will break a fan's heart by beating his beloved team. But that should never keep a true fan from respecting and admiring that player.
Unless he had purple lips, cheated repeatedly, and was a major d-bag, of course.