I find people like that also annoyingly tend to rewrite their own history to fit it into their new 'sober' narrative. They will claim that EVERYTHING about their drug use without exception was just always awful and bad and a disaster right from the start, and how much they hated doing it etc which we all know isn't true. Using isn't like voluntarily hitting yourself in the head with a hammer.
At some point, on some level, you MUST have liked it and it was giving you something, or at any rate you felt like it was giving you something, or you wouldn't have kept doing it. Nobody gets addicted to shit they don't enjoy.
That's where I think most rehab programmes go wrong from the get-go, because the focus is on abstinence through shame and fear, so they really push the negative angle and insist you view all your escapades purely through that lens, and that distorts the picture. The first step to changing your behaviour in a healthy way is to own it. I'd say start by admitting that you bloody well liked it, and be honest with yourself about the reasons why, instead of blanket self-condemnation. Fact is there's positives to drug use, even if you end up in a situation where they are cancelled out and overtaken by the negatives, and it's best to acknowledge this.