Does it have to be deemed to be taxed?
Like others - good question! And Rossum points to it - it has to be made into a 'sin' - ie
deemed to be tobacco - in order to justify the level of taxation they would like (ie
need - to replace the loss of people moving away from cigarettes). They can't make it a 'luxury tax' (like yachts) because they know the average income level of smokers who move to vaping.
Plus it explains in part the demonization that has occurred. If you are a cockroach, (instead of a human) it's easier for them to step on you and the tax then is justified in the eyes of others.
And all of that is just the opposite of the reality of the situation. Rather than a sin, it is nearly, if not actually, a virtue - a 'harm reduction'; a money saver, a cleaner alternative - it neither offends or harms anyone near. It has created thousands of new businesses and jobs. It is innovative and creative. It offers teens who experiment, a healthier alternative and it is not as addictive as cigarettes.
Were it any other product, they'd be incentivizing or subsidizing it, rather than taxing and regulating it.