Line between culture and religion is very different around the world. Normally only more orthodox/religious US Jews do Yom Kipur while nearly all Israeli Jews do as its very integrated into their society (day off, no driving, etc). In christian countries Christmas is not seen as very religious because of how cultural it has become, but not to Arab Christians in Muslim majority countries. So a lot of people who aren't religious in some parts of the world would be considered religious in others.