That's an interesting distinction. Many people drink in moderation quite successfully without ever being addicted and without ruining their life. How many people successfully maintain a moderate heroin habit?

The distinction, at least to me, comes from the fact that alcohol is more prevalent, and even though the rate of addiction may be lower, still harms more lives given the much larger population of people who consume alcohol.

That is exactly my point. Additionally, if you do want to look at things statistically, alcoholism is far more prevalent, at least in the United States, than heroin. In terms of raw number, alcoholism affects are larger range of people and arguably therefore destroys more lives.

That's hardly a correct comparison. Alcohol is far more readily available and accepted than heroin.

Hence, if you consider the effect on the entire using population, alcohol has a greater potential for damage considering its greater availability. Heroin is a bomb. Alcohol is fireworks. One is legal, and arguably less dangerous, but there are far more fireworks injuries in the ER than bomb injuries.