When it comes to picking things you are spending your free time on, movies, dining out, video games, books, etc. you are more likely to immediately not even consider stuff you strongly dislike. Its really frustrating to see things in lists you wouldn't even consider. You lose any hope in that system being able to help you find something to escape reality for a while.
What is needed is a movie pick service and that starts with asking what genres you hate. Then get into specific movies you hate to further refine the list of things I don't want to see but at the same time clarifying questions to narrow down the like/dislikes because there are movies that combine elements from different genres. For example, The Joker could be considered in the #superhero, #sad, #mind-fuck categories and if you like #superhero movies but strongly dislike #sad and #mind-fuck then those should be weighted higher and the system shouldn't show The Joker on any personal lists.
The service should have an unfiltered search so people can just find stuff too.