AF because you wouldn't tell a depressed person to snap out of it, in fact it is quite the opposite of what psychiatrists advise, you also wouldn't tell an anorexic to finish their 3 course dinner, so telling someone in a codependent relationship, living with an alcoholic that you yourself wouldn't put up with it and to just leave makes just as little emotional sense to them. You get heavily caught up in the denial and think that because you love this person you can help or change them or that it is just in your head and not real, and this becomes an obsession that takes over. Similar also to a DV/abuse situation I think. That is why alcoholism destroys families, the partner is just as affected and frankly traumatised by what is happening, and that is why you need to detach and need proper help to do that. If detaching was easy, there wouldn't be support groups like al anon and coda and a long 12 step programme, because like snowiebear said you 'sink deeper and deeper into a circle of lies and despair' until your own health suffers. And getting out of that is very hard and can take a long time to do properly.
So yes we are 'saying the same things', but sometimes your (often correct, often very good) advice can feel like a hard painful (not needed) smack to the head because it is so to-the-point and personal with all the "I would's & would nots".
And I am saying this as someone who is in a similar situation as highwaster, although possibly a little bit further down the line. A year ago Attila gave me similar advice on a post I had made, and even her direct (and non-personal, oft repeated) approach made me want to scream and shout out that she was wrong, she didn't understand, my situation was different. tbh it made me nearly hate her. So I ignored it, it was far too hard to take. Or too hard to do anything about. And I read lots of posts about alcoholism and thought not like my situation...
And now I have reached that 'own health suffering' stage. Or my breaking point perhaps. So I am going to finally get the help I need and have taken the necessary steps. But the way you personalise and preach even now makes me want to run straight back into denial. It is too difficult to hear how I could have messed up and someone else would have dealt with it easily. People who become codependent, as I understand it, are often susceptible because of background/upbringing issues, so yes in your situation you wouldn't put up with it. Good for you. And I am not going to apologise for being frank and you can ignore me or shout back if you prefer. But when someone reaches that stage of absolute desperation, support and a gentle approach might be more suitable, instead of multiple posts of I could do it better.