I would submit that “harm reduction” is a very charged term; however, I would submit that any form of treatment is necessarily harm reduction. Whether you're taking methadone or Suboxone, or psychosocial support, or whatever it might be, I would suggest that yes, it does need to be a pillar. Does it need to be specified? Yes. However, I would suggest that for a variety of reasons the term “harm reduction” rubs some people the wrong way, and they don't understand it.
I think when you look at anything, you are lessening the harm to somebody when you're getting them into some form of treatment. Whether or not you want to officially call it harm reduction, or you want to put it into a pillar, or this, that, or the other thing, the reality is that if you're in any form of treatment, you're necessarily in harm reduction.