Precisely. Hanzo is a difficult hero to play well, he is very fragile with no defensive talents, and his one conditional mobility is on a long cd.
I would say the Hanzo effect is probably similar to the Li-ming effect - he is a popular hero with a low population that can play him at a high level. Although I can’t explain why KtZ would have a much higher win rate with otherwise similar stats. Maybe looking at hero level would explain it better - as in more low hero level Hanzo games being played (< lvl 10) and higher hero level KtZ games (lvl 10+).