When I'm looking for new employees I try to be upfront with applicants by letting them know that I don't hire "Rick and Morty" fans.
Um, that might not be legal. Why don't you hire "Rick and Morty" fans?
I think they are extremely rude people.
Not liking an entire group of people just because they like a TV show is wrong and will just make you look petty to other people. You're also losing out on potential good employees if you refuse to hire them. You should be more open minded to people with different interests than your own.
Nah, rudeness has been proven in that type of  people.
This doesn't seem like a sound business policy to me. You need to base hiring decisions on a person's qualifications only. That's an extremely large chance that you'll misjudge someone by basing your opinion on their show choice.