When drinking becomes addictive, either psychologically or physically, it's considered alcoholism. Alcohol abuse, if left untreated, can progress into alcoholism. Only people who are morally weak or have emotional problems can become alcoholics. In most cases, emotional problems are the result of alcoholism rather than the cause. What's important is how much and how often someone drinks, not what kind of person they are.
Alcoholics do it to themselves.
Nobody forces them to drink. They could stop if they wanted to. Again, we can choose how much and how often we drink, but we can't choose how our bodies will react to the alcohol. Some individuals can drink more than most people and never become alcoholic. Others, with a higher level of biological risk, can become addicted much more easily, even though they consume less alcohol, less often.