righteous indignation

What motivates people who dislike a popular TV show, movie, musical artist, TV or movie actor, etc. to go on the internet and voice their dislike. You'd think it would be as simple as "watch something else on TV", "don't see that movie", "don't listen to their music", "don't watch movies and TV shows that actor is in". Instead, some people have to use their dislike to feel superior to those who have completely different tastes.