I agree with 99% of what you said, but in the case of weed, while I don't think it should be hidden per se, it has a known "secondhand" effect on those in close proximity.

So perhaps it stands to reason it's just the usage that should be kept at a distance rather than the admission of use. Too bad so many are still terrified to admit their use where it's still illegal. May that change more rapidly in the future.