Let's work through the logic here: San Francisco assumes that the existing controls on the purchase of tobacco products by minors are a failure. They must act. San Francisco's reaction to this is to ban all tobacco products from the city, for the children. This is perfectly rational. But wait, no, their reaction is to ban the harm reduction option and keep the worst tobacco product known to be the most addictive and…
Vaping plus flavored nicotine is marketed at kids. If vaping were strictly an alternative to cigarettes, marketed at existing smokers, as a harm reduction alternative then it would be fine. But it's not, it's marketed as a hip new thing, getting kids hooked on nicotine that would have otherwise never touched a cigarette. Also, that flavored nicotine smoke smells nasty. Most smokers tend to be aware that people don't…
Let's assume what you say is correct, that they're marketing it for kids. The correct action isn't to ban it, it's to ban the marketing.