The owner of Max's Deli in Chicago posted a tweet that tried to make a joke out of the mass murder of Las Vegas concert-goers. Here's the story.
Business-wise, the deli owner is an idiot. He made it hard for even his best customers to order a sandwich. As a result of his racist, insensitive, cruel remark, his restaurant was pounded with one-star reviews (that's fair) and he received death threats (not cool). Social media, when it reacts badly, reacts very badly.
Avoid anything that makes it harder for your customers to buy from you.
Humanity-wise, he's in need of some serious coaching. Personally, I hope his parents are around to rip him a new ass. I hope he has a friend who will tell him off. I hope his neighbors and customers let him know, face-to-face, that his behavior must change immediately. He is unlikable today, but there is hope for tomorrow.
He has taken down the post and apologized, and that is a good start. Truthfully, who among us has not said or done something we regret?
When you mess up, clean up.
A restaurateur should know that, at least.