They do have that right. Just not in a community where irresponsible use of a drug results in harm of others in the community. This would apply to narcotics that when used irresponsibly, result in citizens that are a risk to others, or to antibiotics, that when used irresponsibly can result in creating immune bacteria that cannot be cured by simple antibiotics anymore, ect, ect.
Alcohol fits that description better than many illegal drugs. Do you support banning alcohol?