My take on this is a little different and I'll probably catch flack for it but.....
Of course a host has every right to allow or disallow whatever they want in their home. However, whether something smells bad or not (aside from the universally really disgusting smells, i.e. vomit, etc) is pretty subjective. For instance, if I were a guest, I would find the smell of air fresheners, Bounce sheets used on bedding and towels, scented toilet paper, booze, or vinegar to be very objectionable, yet the smell of marijuana wouldn't phase me at all, even though I'm not a smoker. I have a friend who can't stand the smell of coffee.
To tell a guest that they can't smoke marijuana, even outside, even on the street in front of the house, and can't even vape, in places where it is, in fact, legal, is in my opinion, pretty over-the-top controlling.
As a huge percentage of the population uses marijuana either recreationally or medicinally, hosts forbidding it in any form where it is legal may see a reduction in bookings.
