Notice. This store is politically incorrect. We say Merry Christmas, God Bless America, we salute our flag & give thanks to our troops, police officers and firefighters. If this offends you, you are welcome to leave. In God We Trust.Like anyone care if they say "Merry Christmas" to you in November or "God Bless" or whatever. And when did it become "politically incorrect" to support the troops or the police or even the firefighters?
A business owner is more likely to get picketed these days by activists for telling someone "Have a nice day" as opposed to "Merry Christmas" than the opposite. Most people don't care. Offer the salutation that feels most natural to you at the time and move on like the rest of humanity. It will be okay.
But signs like this really rankle me. You, the business owner, just challenged me, the customer, to a political pissing war. I don't like to spend my money in the location of a political pissing war. Instead, I go to the bakery (or whatever) that doesn't instantly challenge me to assess my own political views before coming in to buy my donut or cake or whatever.