Sorry Paul it is you who do not seem to understand. It is attitudes like yours that perpetuates the problem and confuses this issue. People start to take drink or drugs simply because their peers do. Many of the reasons you seem to dismiss as not applicable are actually the root causes.....not because they have mental problems or a predisposition first...the mental problems associated with addicts are as a direct result and side effect of taking the drugs.
I agree that in some cases alcohol can be worse than heroin or other drugs. That said the vast majority of responsible people can have a beer or two or a glass of wine now and again safely without doing their moind or body any harm....it is those clowns who binge drink who have the problem...and again it is down to education and peer pressure to make this phenomena a taboo. Evidence has shown that legalisation or even prohibition of alcohol or drugs does nothing to diminish the problem. The only thing that might work is education and a change of attitudes to what is and what is not acceptable behavior.....we cannot send out the wrong messages to our young and impressionable.
Addiction IS a moral issue.....and should be higher on the agenda of things to eradicate from any society.