The point I was making there, is that accepting responsibility for resolving inconsistencies is up to them .. its their choice and doesn't come down to trusting someone else's opinions of 'what right is' and 'what wrong is' and others' (or even their own) judgements about 'how much they know/don't know'.
The latter basis is less motivating (particularly in dealing with addictions), as they may not have the detalied knowledge needed for convincing themselves to the point where they'll stop (from their viewpoints, they're most likely just going by abundant hearsay/hype). Its also demotivating, because it negates their sense of personal freedom to acquire that knowledge for themselves, (or even worse/insulting: being made to appear as though they are somehow deficient in knowledge on the topic).
Their reports of their 'struggles/difficulties', tends to be a sure sign that their mind has set up a smoke screen of confusion, in order to avoid accepting the responsibilty for their actions. (We all do this).
The pre-requisite conversation might be along the lines of: 'Do you consider yourself as living a life of integrity?, (where by 'integrity', I mean a deep sense of completeness and wholeness), as this taps into less sensitive parts of their knowledge and is also the tip of a huge iceberg affecting other areas of their lives).