Perhaps you’ve misread, that’s included in the ‘single’ part. Regardless, my larger point is that when you’re at a bar you’re not going to walk up to a random table and ask a guy out when he’s holding hands with some girl. People who are single and looking do just that - they look for signs that the other party may be interested. It takes some social skills, but as the original article shows a large proportion of couples meet in a bar, so clearly it’s not impossible.