Most people would think it a gross infringement on their basic human liberty and dignity if they were to be arrested and charged with unhealthy eating.
Why then do we think it reasonable to arrest an adult for the heinous crime of smoking marijuana? Why do we think it reasonable for the government to apply criminal sanctions to an adult for taking an ecstasy pill?
Why do we apply a different standard to the liquor merchant or tobacconist than to the ecstasy or marijuana dealer?
Surely it must be that marijuana is far more dangerous than tobacco or alcohol or horse riding: so much so that the government is justified in imprisoning people for selling these products to adults.
The truth is that marijuana is significantly safer than both alcohol and tobacco, and immeasurably safer than mountain climbing. There has never been an overdose of marijuana, whereas deaths from alcohol overdose are commonplace. Likewise, while ecstasy has some risk associated with it, it is not nearly as dangerous as horse riding, alcohol, tobacco smoking or many other activities that we consider worth the risk.
While there are risks associated with all illicit drugs, many of these risks are generated or exacerbated by the prohibition rather than the substance itself.