That may be true, but not everyone believed it until years later. I see parallels here with skepticism we see of research done on vaping. People are skeptical - just like they were in the 40's.
The only parallels I see are the tactics being used. Granted as cigarette smoking became prevalent
during the WW's of the last century the apparent harm started to become evident. Remember though
it was cigarette smoking and inhaling of the smoke thought to cause harm. Prior to cigarettes
cigar and pipe smoke generally were not inhaled. They still are not. Even today it's not quite clear
just exactly what and how much harm inhaling cigarette smoking actually causes and simply
exacerbates.
When it comes to vaping there is absolutly nothing comparable scientifically in terms
of observable or provable toxicity or illness and modern toxicology and scientific methods
are far more advanced than the mid 20th century.
The demonizing tactics used today are the same when used against cigarettes
when it was realized the onerous taxation and utter control that could be wielded
against a minority bereft of saving grace as being an ignorant addictive second
class sub-species of mankind.
Am I skeptical? Believe it. I have lived through this before.

Regards
Mike