Shame due to what? Because they are suffering somehow or because they feel like it must be bad for them because they enjoy it?

I can’t speak for them, there are a variety of reasons they might lead to it. But I do see shame/regret being the emotion.

An example could be that they don’t like admitting how dependent they are on it to function. Reading between the lines, this is vibe I pick up most. Some others in the comments have stated this explicitly as true for them as well.