so much bullstuff lol
It's not really that hard to believe considering people smoke hundreds of thousands of more cigarrettes over the span of their life compared marijuana smokers, who smoke exponentially less than that. Like I said before:
You'd have to smoke ridiculous amounts of weed daily to make that study relevant at all.
According to a survey I found online the average smoker smokes somewhere in the range of 10-20 cigarettes per day.

Let's say 10 cigarettes per day just to make it easy on me. If you dump a cigarette out on a scale it'll weigh around one gram and about .8 grams of that is tobacco. .8 multiplied by 10 is 8 grams of tobacco per day for the average smoker. That's 2920 grams of tobacco smoked per year.
After a little research I've concluded that the average marijuana smoker smokes around .6 grams of marijuana per day, which would be around 219 grams per year.
That's 13.33 times more tobacco smoked, and 2701 more grams of tobacco smoked per year than marijuana. Up that to 40 years of regularly smoking and that's 108040 more grams of tobacco smoked than marijuana.
Multiply 219 grams of marijuana smoked per year by 4 to get the equivalent of 876 grams of tobacco smoked per year based on the amount of tar deposited. That's over three times more tar deposited in the lungs for the average cigarette smoker compared to the average marijuana smoker, and that's not even taking into account that more people smoke 16-20 cigarettes per day compared to the 10 cigarettes per day I used in the data.