The first reference in that article is to a behavior. It’s not IS’s fault that there are a lot of articles denigrating people with NPD for displaying that behavior. The behavior itself is an issue, whether or not the person doing it has NPD. A job interview is an example of flattery and manipulation, and that’s why nobody expects them to be an absolutely accurate view of a person.
The second reference is a language issue and it’s a valid point. “Narcissistic” is a loaded term, in that it’s both a diagnostic descriptor and a colloquial term, and it’s easy to simply substitute it with egotistical or self-obsessed, which don’t have additional medical definitions. This is the absolute first time this has come across my radar, though, so I wouldn’t be hugely surprised if it’s also not on IS’s radar- the author of that piece ascribes it to hate, but that seems like a real stretch.
I watched the video, and then visited the sources. This seems like a good candidate for the psychology of the video, but frankly, there are a lot of sources that all describe the methods of alt-right actors online. It would be great if it was better sourced, but it’s a quick video that doesn’t cover too much new ground.
The title of the article is also misleading- the author notes a poorly cited video and two microaggressions against people with NPD, but those aren’t reactionary things imo.