From a Christian view, the opposition is to drunkenness, which is depriving a person of reason. I think most of the people seem to argue cannabis basically always produces drukenness of sorts, although I have known some people to seem to be able to reason while high so I am not sure if that would be akin to a lesser “being buzzed” or not. Many Christians who are against “drunkenness” avoid getting high since they think it will create a state of drunkenness, hence there are probably a lack of people who can speak “from experience” on if such drug creates drunkenness or not in lower doses, who are also opposed to it.