All the while (half the?) bochurim in Lakewood and other yeshivot are taking cigarette breaks on regular -- and even hourly -- basis.
But weed? You're no longer part of our community, you terrible sinner! Cheirem!
Never mind that the lung-health risks of smoking weed appear "relatively small" and "far lower than those of smoking tobacco" which is the top cause of preventable death in the U.S. It's like ER doctors focusing on the paper cut instead of the bullet wound.
Nowhere close to half of boys 22+ in Lakewood. The vast vast vast majority of boys stop before commencing shidduchim.
The likelihood of cigarette utilization, even when used on a regular basis from age 15-22, having a significant detrimental affect to one's health down the line, is extremely low. Most smoking related diseases do not manifest before close to 50, and do not have more than a 25 year lookback.
Smoking may be a bullet wound in greater American society, but in American yeshiva circles, where boys, if they do smoke, do so mainly between 15-22, it is a paper cut.