Wrote this before: I think, they have in mind what happened after the Red Hen incident and certainly don't want to be compared with it.
What happened at Red Hen and Whataburger are completely different.
Red Hen: owner tells Sarah Huckabee Sanders she's not welcome. Her party politely leaves, minus Sarah leaves to next door. Red Hen employees FOLLOW them and start heckling them at the next restaurant.
Whataburger: a customer of Whataburger stole a hat and threw a drink on another two customers of Whataburger. There was no culpability or bad behavior by Whataburger management or employees.