A lot of people come to this site to learn how to drink in moderation. I couldn't begin to count the number who come through the doors of AA to learn how to "drink responsibly." These people realize that they have a drinking problem but are trying to find an easier, softer way to fix it. When you mention abstinence they freak out. Most will eventually be honest with themselves, but right now they're at the early stages of denial.
All we can do here is suggest they look at the possibility they're alcoholics, but very few do that. Some will eventually get it and accept the fact that they suffer from alcoholism, but it takes time. Many more won't get it and alcohol will either institutionalize or kill them. I've never come across anyone on this site who calims they can drink moderately. I've seen a whole bunch who've tried and failed, however.
You're right about taking that one drink. For us serious drunks that would be suicide. It's something that everyone here realizes. Everyone except the newcomer. But don't get too wrapped up about this. I think a vast majority of people will eventually come to the realization that they have a serious problem. It's our job to be around when that happens.