As I've said...this was written in the 1940s, when alcohol was pretty much the only intoxicant that was widely available. It's a total anachronism. If AA had been more open, maybe those who became hooked on "mother's little helper" in the late 50s would have had somewhere to go.
Many people are cross addicted to substances with alcohol.
The segregation is just silly to me. At least CA lets anyone come and share about whatever addiction they feel is relevant at the time.
Addiction is addiction.
In any event, saying that someone who got high is sober because they didn't drink is a far too literal reading of the tenets of AA.