I actually support broader legalization, but this doesn't take anything from the argument. And with alcohol it's a different situation - it's not that "some can

I actually support broader legalization, but this doesn't take anything from the argument. And with alcohol it's a different situation - it's not that "some can't handle it", it's that "some feel compelled to use it". A closer situation would be when a non-smoker feels left out from the social life at the company and actually can't advance his career because he's not part of the smoke breaks. Sounds ridiculous, but people have started smoking for exactly this reason, and some/most of them have worse health because of it. Now this is relatively indirect, but compare it with a situation when everybody at a company is easily able to pull 20 hour days in the week before launching a product. Even if you feel you don't really want to use drugs, can you?