8th amendment doesn't give the government any right to define "cruel and unusual punishment", therefore that is left to the people to interpret. In OP's case, removing the ability of self-defense from people after they already suffered from years of unjust persecution from a drug-related non-crime certainly fits the definition of "cruel and unusual".
Yeah, and it's our state legislature elected by citizens that sets these laws ....your point?
As a citizen I believe he's lost his right through his own actions heroin in particular is a nasty drug.
Freedom isn't just a right it's a responsibility if you are reckless, stupid, mentally ill then the system steps in and you loose some or all of your liberties.
Then there's the issue of unjust laws, which you seem to dismiss offhand with "due process". As if a bunch of fascist bureaucrats running their "process" explains the dubious morality behind the drug war and removal of human rights from anyone who offended the government.
Define unjust law?
This often comes down to state laws via reciprocity or adoption of fed laws often in exchange for "fed funds"
For decades this state and others have made marijuana illegal and now have decided to change these laws
and the fed's are powerless to stop it.