As a regular smoker I actually agree. I hate seeing people smoke and shit before doing something that requires coordination, planning or thought. Drivers in CA I'm looking at you. Yes there are people who are functional enough to get by high but that doesn't mean they are "optimal" when they are doing it.
Now there is a whole category of things I'm happy to do high. Shopping, eating junk food, watching reality TV... all great high activities... just not particularly productive in the first place.