Here's what I sent them:
You have apparently decided to ban guns in your establishments. That's too bad.
It means I and my family will no longer be able to dine in a restaurant we otherwise have always enjoyed.
Perhaps it should be brought to your attention that such "gun-free" locations have been the sites of almost every mass killing in recent years. Coming to your establishment and leaving my legally carried handgun at home is simply not an option.
I understand the emotions driving this decision, but you have made a mistake, and I won't allow my family to be targets because of your inability to withstand a bit of public pressure.
Good luck. If you change your plans, we'll be back.
Thanks to the OP for providing the link.
"The welfare of humanity is always the alibi of tyrants." Albert Camus