Show me a study that says that nicotine, by itself, is harmful and/or causes physical dependence. When restricting activities based on potential for harm, the onus should be on the regulator to prove that the potential for harm exists, not hypothesize based on a tangential connection to another product as is the case with nicotine and smoking. Caffeine, depending on your definition, is not addictive. It is habit forming, it does produce short term physical withdrawal, but is generally recognized to not cause harm, unless of course you overdose.
Even if one Completely Agrees with this, can the Same thing be said about EVERYTHING else that is Inside an e-liquid?