My guess is, this dude is going to go tell all his buddies about hanging flyers and will be sure to mention the dick who asked him to buy food when he asked if he could hang a flyer. In his eyes, your business is not a community friendly place now and you are a bit of an ass. Not saying that's true, but that's how he will probably project it.
Next time, I'd be friendly and say "Sure. While you're here, care to place an order?
If he says no, wait for him to leave, then tear the shit down if you want, but act friendly towards the community up front and it will pay off.
Example... a local bakery in the town I live in has been there and owned by the same old guy since before I was born. Family business passed down to him and eventually I'm sure to his kids. First time I ever stepped in there was when I was out begging for donations to help fund my kids non-profit wrestling team to help host their home tournament. The guy wrote a check for $50 and also said anything we buy for the concession stand from him will be buy one get one free.
So we got some doughnuts and other shit to sell. Since then, every b-day cake I've bought for my 3 gets has been from his shop despite his place being the most expensive in town. 5 years in a row now he has donated to our tournament, and I encourage everyone to go there for b-day cakes and shit. He didn't ask for that promotion, he was just friendly and made a donation and offered us a discount. From that, he now has some new customers.