I would say its a half-truth at best.
Are there people who struggle with the sacrifices needed to pursue a career in surgery? Absolutely. Are there people who have interests outside of surgery who are successful in training and beyond? Also yes. Are there people who are 100% committed to surgery and have no outside interests and subsequently quit? Also yes.
I think that it just depends on how much it bothers you that you don't have time for those activities. If you're a competitive runner, will it bother you that you will be jogging (not running) once a week. If you're a musician, you might be talking about playing your instrument once a week and not being near the level you once were. If that's a problem, then you'll struggle. In my opinion, its not the hours spent in the hospital (which is a lot) that is an issue. Its the hours spent in the hospital when you're trying to be somewhere else or wishing you were doing something else. Unfortunately, for some people this is every moment they are in the hospital. For some people, they pursue fields that are more lifestyle friendly because it gives them the opportunity to pursue these interests. The problem is that their interest in the field is limited, so they spend the entire time at work wishing they were pursuing their outside interest.
I think there's probably also some degree of interaction with a variety of other factors: family, individual resilience, co-resident camaraderie, and the program feel.