I've often felt ostracized at my employer just for not following the rite/folklore of lunch together. Joel has a conflict of interest. As owner of course he stands to benefit if his employees went for lunch together, because inevitably they'd be talking about work, maybe even solving work-related problems in the process. While lunch is a great occasion for socializing - it'd be best to be up to the individual on how to spent that time.
You nailed it. I think Joel as a business owner likes to have all his staff eat lunch together, because it helps "build team" and lets him evaluate all of them further in an alternate setting. It's beneficial for him. But it's not necessarily the best thing for each individual employee.
