Why should downloading movies be stopped?

Answer 1

When movies are downloaded, the studio or other rightsholder loses the opportunity to recoup the enormous expense of having made the film. If it's a huge studio that can afford the loss, the public suffers in the long term because they might decide that this type of movie isn't popular, and stop funding them. If it's a small studio, they might not be able to handle the economic hit at all, and need to shut down.

In short, downloading a movie now limits your choices in the future.