Your view is quite myopic. And frankly, "if they don't they certainly will not be productive and probably not creative" is rude and insulting to many of your colleagues. I'm going to assume you are young and inexperienced.
For one, some engineers are grown adults with families and full lives outside of work, and they choose not to spend their free time coding. Some of the best engineers I've worked with fit in this category.
Secondly, I'm sorry, but it sounds like perhaps your work happens to not be very interesting or challenging. That is not the situation for everyone. I solve interesting, challenging, diverse problems all the time at work, on proprietary codebases that cannot be shared.
I launch startups. At least one every 5 years since I was 17. I am very passionate about whatever I do or don't do it. I'm approaching 50 years of breathing.
You may dislike my tone but remember the context of the post - If you have nothing outside work for someone else to offer for your accomplishments it is you who are young or have done very little with your life.
I'm not sure who you've met who fits the criteria of being by rule not creative or productive if they choose not to dedicate time outside of work to coding (not that they have done _literally nothing_, just that the things they have done are not closely correlated with their work, and would therefore be irrelevant in this technical interview context), but I would suggest that on the whole you are drawing too coarse a stereotype and are therefore missing out on a large pool of talent. But to each their own!
For one, some engineers are grown adults with families and full lives outside of work, and they choose not to spend their free time coding. Some of the best engineers I've worked with fit in this category.
Secondly, I'm sorry, but it sounds like perhaps your work happens to not be very interesting or challenging. That is not the situation for everyone. I solve interesting, challenging, diverse problems all the time at work, on proprietary codebases that cannot be shared.