I suspect geography determines the politics of a chain's patronage as much as the chain itself.
According to its website, Cracker Barrel, cited in this article as having the most conservative customers, has no restaurants in California, Oregon and Washington and has only nine in New York; yet there are 47 in Texas, 50 in Tennessee, 42 in Georgia and 29 in Alabama. There are quite a few in the current swing states of North Carolina and Virginia as well.
I think Cracker Barrel knows its clientele and locates accordingly.
The Op-Ed article and accompanying bubble graph were interesting, more so for their construction. They included Whole Foods, a store among restaurants and whose data were based on seven days versus 30 for all others. Why? Would the high-turnout Democrat square look empty otherwise?
Why leave out Southern California-based chains such as Carl's Jr. and In-N-Out? Based on the top 100-ranked chains by Nation's Restaurant News, the writers included No. 76 Boston Market and No. 80 White Castle but left out No. 3 Starbucks, No. 24 Chipotle, No. 25 Papa John's and No. 26 Buffalo Wild Wings.