I fail to see how Sunday closures are progressive at all. If the total amount of time off isn't greater then it doesn't benefit workers more to have Sunday off as opposed to Friday or any other day of the week. From a utilitarian perspective having a restaurant close on the one day that most of their customers have free time to visit is highly inefficient.
If you work shift work then having Tues & Weds off while technically the same as Sat & Sun off (2 days off in a row) it is a tangibly worse "weekend".
You may have 2 days off but your friends and family are likely working during the days and in "nothing too exciting" mode in the evenings.
The benefit of everyone having Sunday off means that (for the most part) the rest of the world also has Sunday off and you get to enjoy time off with your friends and family.
I've worked shift work with only Fridays off before. It was not tangibly worst than having only Sunday off. In fact I would say it was better because dealing with certain government bureaucracies that close down on Sundays was significantly easier. You can't expect the entirety of society to shut down on Sundays so there's always going to be somebody who has to work during that day.
Doing something that doesn't benefit the customers but does benefit your workers (because not all days off are equal) is pretty progressive. It's not necessarily their intent as an organization, but it is the effect.
