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!