The short answer is movie theaters can make money being open on December 25 but most retail stores would not.
In the United States, retailers close their stores whenever they believe their consumer base will not be visiting their stores. When the population of the US identified themselves as primarily Christian and it was socially unacceptable to not be at church at the appointed times for services/meetings/gatherings, retailers would close their stores because everyone would be at church. This is why stores have only been routinely open on Sundays starting in the last few decades, and currently many stores are open only in the afternoon on Sunday. December 25 (Christmas Day) also falls into this category - most people (of any religious tradition, including no religion at all) spend December 25 with their families and won't be out shopping. However, movies are one way people spend time with each other, so enough people will see a movie on December 25 to make it profitable for movie theaters to be open that day.