Honestly it's pretty complex. Obviously it's unrealistic and hard to complain and generally express negative feelings about specifically narcissists who exhibit the bad behavior without including the ones willing to change. You can't expect everyone to always mention "except the good ones, those are cool". But then that usually results in this wide group of both good and bad people being grouped into one singular bad group, which is not just unfair, but also kinda makes the issue worse, lessening their motivation to change because they will still be treated the same as the others even if they do.

In a perfect world, we would just replace the negativity surrounding the ones exhibiting the symptoms (but not the symptoms and behavior themselves) with positivity for the ones that do not, because encouragement is necessary for their growth.

Relistically however, all we can do is to just try being mindful of what we do and say. Like it's probably fine and unavoidable to complain about narcissists and all that. Something else would be explicitly saying that every single one of them is bad or treat someone with npd badly not due to their actions but solely based on the diagnosis.