His argument is that he and others like him will be forced onto the black market. I agree, that's not right or helpful.
But he's only bothered about prohibition now because it's his drug of choice which is affected.
Why did he not raise the issue before, for those people who use cannabis to combat the symptoms of MS, or Cancer treatment, or AIDS, or PTSD, or Chrones, or Epilepsy.
He uses poppers to assist him in anal sex, fair enough. But why is it on the one hand wrong to push him onto the black market for his anal sex drug, but on the other hand it's Ok to push patients with legitimate medical needs onto the black market for cannabis?