I think the idea is that alcohol can alter the biological function of the body. Being drunk limits the capacity of our moral agency. I think that the general idea would be to jsut avoid it altogether to eliminate the problem. It's kind of the same idea with teenage sex statistics, the only way to really prevent it is to abstain entirely from it.
Alcohol also tends to be a gateway into more severe behavior and problems. Things like alcoholism affect entire families and since alcohol provides no benefits to health, it is just omitted.
