I think the point is that we accept that making something cheaper or easier tends to increase its usage on the margin. The reverse effect is an extraordinary claim that should be met with skepticism. Individual success stories shouldn't be enough to persuade you.
If a small number of people do drugs who wouldn’t have before, but a large number of people who are addicts manage to get clean or no longer die, then is this a win? This post, in my opinion, completely ignores the idea that a government program might be nuanced.