It's completely understandable people like yourself having this opinion, maybe a close friend or family memeber has gone down the dark road of addiction, i get that.
However, the times i've used party drugs i've had a great time, i'm a big boy and understand the risks, it's not as cut and dry as you suggest. Do all people that have one beer turn into alcoholics? NO. Are people able to have a social beer without turning into alcoholics? YES
The event that happened to the the person in this story is, of course, very unfortunate.