My extended family gatherings are like a medical convention. Both my parents are physicians. Unlike computer science there isn't a question of "do I need to work on medicine to continue to be on the top of my game?" The answer is yes. Period.
As far back as I can remember my parents have always had heated medical discussions on new cases over dinner while my sister and I shared blank stares. When I was 6 or so I remember gathering all the copies of the New England Journal of Medicine, Modern Pathology, and the Journal of Clinical Pathology and using them to make a fort in the apartment. The high ceiling fit me and my sister quite comfortably. My mom spends her time thinking about how things could be done better and more efficiently in her practice and my dad is constantly innovating and forming companies.
So do programmers have to like programming? Do they have to keep up with it outside of their job requirements?
Perhaps the difference there is, who wants to go to a physician not at the top of their game for anything beyond a routine physical? Whereas a programmer not at the top of their game can do some useful things and won't kill anyone barring exceptional circumstances.
In a competitive world, if you want to be on top in any skilled discipline you are going to have to put the time in. My family is primarily auto-related, and while they may not spend every spare hour tinkering with cars in their 50s, they can still do it and have certainly booked many thousands of hours not at work doing it. That industry supports even more people who don't really care.
There are many bad doctors too, trust me (my parents rant all the time).
I'm also a corporate drone right now, and my experience is that most of my "corporate programmer" peers check their programming skills at the door when they go home. Adequacy and personal development mean nothing to them so long as they remain gainfully employed. These men and women also tend to be the most boring people to converse with, not because they lack passion for programming, but because they have no apparent passions at all. Any personal improvements are due to system constraints that force them to learn something new to prevent failing a task. The few who strive to improve on their own, learn another language besides Java, have side projects or businesses, or run a blog or whatever...they're the ones who also do interesting non-programming stuff. I attribute it to having a personal drive or being a self-motivated person or having some mental itch that needs scratching. Something that just prevents a person from being happy by just sitting around watching TV.
I think it's more of a pre-emptive excuse, as in : "I don't have time to study outside the office, since I have a life."
Maybe I run into the wrong people, but I've not run into this assumption much (outside of college where kids don't know much about life anyways).If someone chooses to study, be engaged in their domain outside of work, have 'intellectual' hobbies, that's usually a plus in my book.
I'm curious where people have run into this?
Me: 'So, do you have any personal projects that you'd like to talk about?'
Candidate: 'Not really, no.'
Candidate: 'No, I prefer to have a life.'