I'm all for getting kids out and letting them be independent. I would ride my bike to the store across all sorts of roads when I was 12-13 year olds to buy rated R movies and Parental Advisory CDs. ("Mom, I'm going for a bike ride!")
When you add these 20-25mph+ ebikes (they can be easily fooled to go faster than legal) and no prefrontal cortex development the situation can get scary quick. Unfortunately we don't have the infrastructure or dedicated, separated bike lanes that make them safe. so stupid solutions like "banning them" are obvious and lazy but there's not much else to do immediately.