I'd like to think I'm pretty good at programming. I spend many hours a day doing it, have studied it for decades and pretty much have been completely obsessed with computers my whole life.
From that standpoint it's really nice for me to have a few hobbies that are much less intense and where I can be "not good" but just enjoy myself. The position this article takes.
That being said, if I wasn't an expert in my field, I may not be able to find that comfort in being middling at best in other areas. This I think is a lot of people's problem. The fear of failure (and in the west, anti-intellectual culture) stop people from even attempting to be great. Not at hobbies but at everything.
So I think the article is correct, but missing hobbies are a second order effect after missing primary passion.