There is an assumption underlying that statement though. A couple of them.
The first is that sobriety the same as abstinence, and it is not. Abstinence may or may not be conducive to sober mind and behavior, but certain substances (such as medicine that also happens to be mood altering, which is many if not most of them, whether in placebo or directly pharmacological effect) are helpful to sobriety.
A super basic example is methadone. For plenty of people (not all by any means) methadone, which is has a fairly high "abuse" potential (which is why it's so tightly regulated), methadone is super conducive to sober minded thoughts and actions. Heroin is not nearly as such, at least not in the US where we have tried to almost entirely criminalize and stigmatize out way out the a social issue fundamentally rooted in public health.
Another super basic example, ironically, is cannabis. Research shows that states where there is medical and recreational access to cannabis, there is less severe opioid use disorder issues. Correlation is not causation of course, but there is even more research demonstrating cannabis is pretty much infinitely safer than black market opioids like heroin or fentanyl (or fent analogues).
The other assumptions likewise point to a more fundamental question only some people are asking or answering in this thread: What is sobriety? What does controlled* use mean?
If the circumstances of someone life preclude them from achieving manageable, positively empowered practice called "controlled use," impulsive, compulsive, or otherwise uncontrolled harmful drug use is not a wise choice.
However, if the uncontrolled use isn't harmful, or is less harmful than other forms of uncontrolled use, it's still a step in the right direction. Progress not perfection, right?
Perhaps sobriety isn't about perfection (it definitely isn't), but sobriety does involve some degree of growth. Otherwise, if it was just repeating the same old mistakes and walking down the same old streets and blindly falling into the same old holes, well it wouldn't be sobriety.
But if there is learning, growth and movement along the path of awakening self-actualization, of psychosocial or psychospiritual integration, then yeah I think it's fair to label it sobriety.
Thank you SL staff for keeping the real spirit of the rainbow of harm reduction alive on BL!!
*(nothing is totally controlled, after all, but that doesn't mean the chaos has to be super harmful either - chaos can be super helpful when its energy is harnessed by some form of skillful means)