In the restaurant, serving customers with MAGA hats doesn't associate you with them. In the other case, making cakes with messages that promote a certain lifestyle does associate you with them. In other words, you simply serve food in the restaurant. In the other case. you serve food and a message.
Don't forget, they champion public servants who refuse to give marriage licenses to gay couples too. They also think that Muslim cashiers at Walmart should be forced to sell pork and liquor or find another job. It's mind numbing.