Maybe that is true, but what I have seen ( I don’t smoke pot) is that they puff. A smoker inhales more because they take it deeper into their lungs and inhale more frequently, probably 20 inhalations per cigarette. A pot smoker puffs about 3 times to get high.
It depends on the quality of the dope. Pot smokers inhale as deeply as cig smokers and then hold it in their lungs as long as possible. Been there done that. If they are going to pick on tobacco smokers they should do the same for all smokers of anything. And if this is truly about health, which apparently it is not, they should pick on drinkers, fast food eaters, motorcyclists, skydivers, hang gliders, base jumpers, bungee jumpers, scuba divers, surfers, bushwhackers, hornswogglers, horse thieves, bull dykes, train robbers, bank robbers, ass-kickers, shit-kickers and Methodists.