Not at all; I'm speaking directly to your point.
If you're going to compare the benefits of ending alcohol Prohibition to ending drug prohibition, then you have legalize all drugs.
Nonsense. Marijuana is recognized by many as being relatively benign in its effects on society. Not harmless, certainly, but its deleterious effects hardly justify the expenditure of finite public safety resources spent to curtail its use. From what I've seen, the probation/fine/asset seizure gravy train enjoyed by municipal administrations is the more likely motivation.
Legalizing just marijuana is equivalent to legalizing just wine during Prohibition.
Again, nonsense. Just because you say it doesn't make it so. Anyone with a brain can see that marijuana is utterly different in its effects on individuals, and by extension, society, than, say, crystal meth. Not to mention their completely different chemical composition.
Drinking a half gallon of wine does not produce any substantially different result in the drinker than does drinking a 12-pack of beer, or a fifth of whiskey.
Really? A six-pack of beer (72oz) at 4.1% alcohol contains about 3oz alcohol. A half-gallon of wine (64oz) at 7% alcohol would be 4.5oz alcohol. A fifth of whiskey (25.6oz) at 40% alcohol would be 10.24oz alcohol. I would think the physiological effects of the latter would be quite different from the former.