Man, I'm actually catching complicated feelings on this.
Generally, if stores shut back down on Thanksgiving, I would agree with it and feel comfortable. I've never shopped on Thanksgiving and I'm not planning to today.
But as someone increasingly separated from family, I personally have a dimmer view on the end-of-year holidays. I'm not going to change my behavior and shop, but I find the holidays less sacred than others.
My personal animus aside, some people also find the holidays... boring, less-than-special or even eerie (my bustling city feels like a horror movie scene when everyone's indoors). That kind of person may really want to be somewhere other than home and behold, restaurants, malls and other shops are open!
Besides that, casual travel and tourism are part of the holiday tradition for some - so, some commerce is inevitable. People visit the city for thanksgiving or Christmas, and they're going to eat somewhere.