Two years ago, I spent the summer with my cousins in Washington, D.C. There's a restaurant a few blocks from their house called Comet Ping Pong: the gimmick is they sell pizza and have a lot of ping pong tables, and diners can play while they eat. One muggy evening, I walked there with my cousin. We ate pizza and played ping pong. It was fun. Two days ago, a North Carolina man named Edgar Welch walked into Comet Ping Pong and fired an AR-15 rifle, as part of his "investigatio