Normal, everyday people have been riding this way for years. Un-riders ride on sidewalks, and get smacked. In short, un-riders play by a different set of rules, and pay the consequences. Because that's what they were taught as children. As a kid, you learned how to ride your bike as a plaything, and the rules you learned were for kids.
Kids are incompetent when it comes to traffic.
Playing by the kiddie rules as an adult makes you incompetent. It used to be that when you joined a bike club, you learned how to ride a bike like an adult should. What's worse, the child-perspective on bicycle safety leads to policies and facilities that are downright dangerous to cyclists. Planners design on-street facilities like the one being constructed in my neighborhood. There is no provision for left turns, and bicyclists travel straight into the path of right turning traffic.