I absolutely agree with this to be fair. I have been touched by alcohol addiction but not drug addiction. So as much as I personally don't agree with parents taking drugs, I do think the effects of alcohol can be way way more damaging. Most people find alcohol socially acceptable and many of those with a problem either don't recognise it as such or fail to acknowledge its an issue often because "everyone thinks its ok".
Parenting aside i probably have a much stronger dislike for alcohol than drugs, again no I don't take them, but both absolutely wreck lives, one is just more sly than the other.
As far as Charlie goes, someone said earlier about growing up around it "can" normalise it for people and I dare say thats whats happened with Charlie. I'm pretty sure I've seen it said that her dad was a full on junkie so the odd recreational sniff likely doesn't worry her so much.
As much as I can't stand the girl, I do feel very sorry for her in some ways as it doesn't look as though she has been shown a fantastic example of parenting growing up, her mum was on/off with questionable boyfriends and often worked a lot to provide for her kids so they were often left to their own devices (or that is the impression her mums Facebook gave).