People who fill vacuums in their personal lives by smoking pot (I’m not speaking of medicinal uses, or even possible social uses) do so because God isn’t in that vacuum.
The answer here isn’t a prohibition which is a mostly vain whack-a-mole. The answer here is the evangelist who tells of Someone that is more worthy and helpful than pot.
When pot is bad, it is bad because it is too little for us. Not because it is too much.
I don't care why they smoke pot. So long as it doesn't affect my rights or liberties, it is none of my business.