Alcohol is required in many biological processes. Your stuff isn't.
There are no special alcohol receptors in the brain, but there are specific cannibinoid receptors (cannibinoid=cannibis=marijuana in case you were wondering). Now this does not prove that it is a required biological process, but our bodies were designed to use cannabis. Processes that require alcohol make it within the cells, there is no need to import it. So your argument is doubly false.
Sure, we have receptors for very microscopic quantities of various opiads, but the aggregate design is not to consume mass quantities like some cone head sucking down eggs and beer.
Now, regarding alcohol, it's been found in intersteller space. MJ hasn't.
No doubt if it is found you'll want to go there. We will contribute to your trip!