re: WWtOTdo or was I in the wrong?

Your arse should have been run out or never allowed in with sandwiches from somewhere else. The bar carries the cost of operating a kitchen bar and waitstaff for inside and outside tables. They aren't in the business of selling a beer or a coke. If other people see that they provide tables for people for people who bring in sandwiches from Macdonald, other bars, or even your freaking wife's tuna salad sandwich you brought to work, the may as well shut down the kitchen, outdoor tables and waitstaff and work fewer hours as a bar.
You were 100 0/0 in the wrong. I understand maybe you didn't know that selling a coke or beer is not what a tavern does, but think about it from their side.