I know someone posted several pdf documents for you to review. You might also find this to be useful as a source you can cite
E-cigarettes - Science and Technology Committee - House of Commons
The topic of harm reduction in comparison to abstinence is a difficult sell, particularly in the US where any harm, regardless of relative risk, sets people off. Maybe it's a puritancal thing, like you should be able to stop using an addictive substance through sheer will, and if you can't you must be too weak to fight temptation.
We've seen this with Prohibition with alcohol which didn't work out too well, and now with opiate substance abuse where an addict should just buck up and stop using drugs. It's an all or none rigid thought process.
As to nicotine addiction, it's just like any other substance of abuse. Plenty is people may experiment with it, but only a small number go on to abuse a substance or develop classical addictive behaviors. Tobacco abuse disorder is obviously more than just the presence of nicotine alone. There is the habitual and ritualistic aspects that become difficult to separate out. That's probably why vaping is a bit easier for folks to help them stop smoking as it mimics ingrained behaviors associated with smoking that other NRT and drug related smoking cessation aids fall short on.
As far as I'm concerned, whatever product, treatment, or other intervention gets someone to stop smoking is fine with me. Vaping doesn't work 100% of the time and I encourage anyone who find vaping insufficient to stop smoking with to explore any and all other methods out there.