why is diehard considered a christmas movie

Well, the movie takes place during Christmas, and the protagonist, John McClane, is trying to save his estranged wife and their son from a group of terrorists who have taken over a building. It's also filled with humor, action, and heartwarming moments that are characteristic of a Christmas movie. Some people believe that the movie is so popular during the holiday season because it captures the spirit of the season, with its themes of family, redemption, and self-sacrifice.