I believe this is for two reasons.
Firstly, some post here in a panic when they are drunk and at their lowest ebb. Then the next day or two after when they become 'strong' again, they convince themselves that they don't have a problem and so just simply don't come back. That is just the nature of alcohol misuse issues.
Secondly, by the time some with alcohol issues reach a forum, they are often subject to being starved of attention by friends and loved ones who have basically given up on their promises too numerous to mention. That is absolutely understandable. They reach out to a forum and receive lots of initial attention and sympathy and offers/suggestions of help.
That's a wonderful feeling for many at times of despair.
However, many forums out their become a cycle of relapse/attention/relapse/attention.
Consider this: Someone in need of help will receive all the attention and sympathy in the world when they join. However, if they then take the advice and suggestions and get better, the attention and sympathy is lost as the other members (rightly) concentrate on the newcomer. How does someone in need of attention and sympathy get that back? Yes, that is right - they relapse and all of a sudden, then attention is focused on them again. And the cycle repeats itself continually..... One such forum is a 'stop drinking' forum on an international website that I won't mention. Seriously, every day the same old people asking for a 'badge reset back to zero' because they drank. And it goes on and on... doing the same thing that didn't work for them and somehow expecting it to be different, and it won't be different because they may say they want to stop drinking, but deep down they are really enjoying the attention when they relapse. They maybe don't even realise that this is not helping them!
Over the years, I've been on many alcohol forums with that exact need for attention, so I am not being critical of anyone. I, too, got stuck in that cycle. Some of the biggest forums out there are simply satisfying the needs of those who are desperate for attention. They subconsciously reinforce to a drinker that relapse is okay because everyone 'loves' them and they can try again.
The difference with this forum is that it is (mostly) free of that type of attention seeking because we have solutions and suggestions that work. Compared to other forums out there, this forum is small in numbers but seems to have a much better success rate of people moving forwards. As RHGB correctly says, we focus on those who are wanting to get better and showing that they are putting in the action to get better.
I know, for myself, this is because I simply don't have the time to repeat myself again and again to people. Once I have explained what worked for me, if they show no interest in pursuing even the discussion with a doctor about medication-assisted treatment, then I will leave them be and comment no further. It is not my place to continually try and impose my beliefs on someone else, and at that point if they approach me I will help, of course, but I will not take part in the relapse/attention/relapse behaviour because it ultimately prevents them ever trying to truly get better. I want people to get well. I have neither the time, nor the inclination, to play any part in their dramas. Alcohol addiction runs in my family and I lost my aunt during one of these relapses - she fell down the stairs whilst on a relapse and died. So, you can understand that I also have very personal reasons why I will NOT take part in activity that either reinforces relapse is part of addiction, or inadvertendly condones it by the actions of it's members.
Some people's lives are 'ruled' by forums. It's the first thing they think of when they wake, and the last thing they check when they go to bed. In the beginning, this is great becuase that connection is good. BUT, at some point, in order to recovery from this deadly condition, someone HAS to change something and put the action in. When that person makes that change, I will be right behind them 100% and supporting in every way that I can.