I agree that someone who doesn't have side projects isn't as attractive as someone who does, in general. But there are lots of people who don't do any programming once they leave the office (8-9 hours of computer time is more than enough for them). That doesn't mean that they aren't dedicated or that they are a risk.
As someone who struggles to find enough time for side projects, I agree that it isn't necessarily a sign that someone isn't passionate about the job. However, if someone says stuff like "I'd never work on something I'm not being paid for, I'm a serious professional that's irresponsible", its pretty obvious that they don't actually like what they are doing.
its pretty obvious that they don't actually like what they are doing.
My dad has been a mechanical engineer for almost 40 years and I struggle to think of anyone who enjoys their job as much as he does. Yet I have never once seen him do any personal "side projects" that are in any way related to his day job.
Many people truly believe in not doing anything related to their career/job outside of their workplace. They do something totally different instead. One might train for a marathon in her spare time, instead of learning the newest JS framework for example.
The side project concept is fairly unique to digital workers, especially software engineers simple because we can. Noone asks an accountant or a secretary for side projects.
pretty obvious that they don't actually like what they are doing
Not to get into a debate, but there are tons of people who don't like what they are doing. But they are still good at it. Sure they may not be truly happy, but they are good at what they do even if they don't like it.
Fundamentally, risk isn't binary. There's more risk and there's less risk. For my kind of team, the absence of side projects, demonstrated lack of interest in furthering one's craft outside of paid hours increases the risk of this person not being able to pull his weight, if somehow he slips through the regular filtering mechanisms. As you pointed out, every candidate presents a unique risk profile, and every company weighs different factors differently.
I work for myself specifically to be able to isolate the kind of developers that will make my organization successful. It's wonderful that we all have the opportunity to choose what kind of environment we want to work in.
I think it should be a case by case basis.