They're open on Boxing Day, as stated in the post. It's only usually businesses run by people that don't celebrate Christmas that are open (like Chinese restaurants, and that one gas station run by a Pakistani family in my old rural town that saved my hide in 2012 by being open after I forgot to get gas on Christmas Eve).
Most movie theaters are open Christmas Day in the US as well, not just boxing day. I've been to quite a few movies on the 25th. Tons of major films are released Christmas Day because it's such a high grossing day in the industry
Hm, I guess I have seen that, but never considered that it could be a high-grossing day. My wife's family would burn us in effigy if we tried to suggest leaving the house during the day so I've never really thought of it much.
If we don't come to Christmas it's as though we've killed the very concept of happiness. We'd never hear the end of it if they found out we went to a movie instead.
I worked in a movie theater as a kid, and Christmas Day was the highest grossing day of the year. Families came in all wearing coordinated Christmas outfits, saying all sad, "Aw I hope you get to spend time with your family today."