For me, yes - it did undermine the case that the author was making. It was sloppy. If he got this one simple thing wrong, can I trust his other complaints?
FWIW, the author seems to be German speaking and in the German version of macOS, Apple actually uses "malware" in their notarization popup instead of the German equivalent of "malicious software" (de: bösartige software).
I think it's very possible that the author changed his os language to take the screenshots suitable for an international audience and did not immediately notice the slight difference in wording.
I had not considered this possibility! Thanks for the call-out. The author's English is excellent, and I hadn't realized until I saw your comment that NeoFinder is indeed from a German site.