Everything is a trade off. If we made swimming pools illegal we'd prevent a fair number of drowning deaths. But the burden of proof should be on the side that

Everything is a trade off. If we made swimming pools illegal we'd prevent a fair number of drowning deaths. But the burden of proof should be on the side that wants to make something illegal. We can talk about regulating use, limiting use through taxation and education etc..., but I think you need definitive evidence of extreme harm that can't be mitigated in any other way before you start putting people in jail for growing a plant.