I mention it all the time, but unfortunately it takes awhile for new members to start to get all this.
Overcoming decades of brainwashing takes time and effort.
A few factors at work here, imo. One, the 'chemistry' is easier to prove/disprove than the 'visual' of smoke/vapor or imo, the lesser factor of hand to mouth stuff.
Secondly and more to your point - the focus by anti's has been on harm and that takes the chemistry route vs. the pleasure of smoking and
vaping, that they tend to avoid and even ignore. And for good reason - on their part. To their 'credit' (yet still skewed) they seem to understand that to have any 'reach' into people's behavior - they have to make some 'harm to others' a prime factor. Harm to just oneself - may be good enough for some puritanical or socialistic minded, but the more classical liberal/libertarian view that what one does to oneself is not government's (or some group's) business, is more widely accepted and so they have to have something that harms
others in order to make their case. They do this by junking their science on secondhand smoke (and thirdhand) and secondhand vapor. Only then can it be considered a 'crime' (harming others) vs. a vice (only harming oneself), which then gives them justification for their intervention.
AND I might add the fact that both of those scenarios (crimes and vices) involve 'rights' - is why you hear little if nothing about "rights" from the
tobacco Control group - either the straight TC faction or the THR faction. The last thing they want to talk about is "rights", since even "harm reduction" with regards to only oneself is also 'no one else's business' but the individual themselves. Yet, it is or can be
in the interest of the individual, to know what harms to avoid or what personal choices to make of 'costs/benefits' whether they want to endure some possible harm for a more real benefiical effect to themselves. So in that sense, regarding knowledge, the THR faction serves a valid purpose and can be a 'brake' on the TC faction, when THR makes more sense than 'quit or die'.