The same dumbness exists on windows where it would silently remove files like keygens with its 'antivirus' making it a mandatory drill to disable it completely on any new installation. Even worse you would sometimes forget that it does that and then be dumbfounded for about 30 minutes as to why the file is in the archive but not on the filesystem after its extraction.
or to not share it with others!
When you actively open an infected or malicious file you do get alerted - those are the alerts shown in TFA.
Could be the PDF example still too, if XProtect misses it on initial file scan, but then Remediator picks it up later. Not sure if they use different detection engines (database matching on the file vs active process heuristics)?
Maybe on macOS it is, and the only reason it isn't broadly knows is because Apple is sweeping this under the rug?
Not to worry! Because XProtect and similar have such a narrow scope, it is unlikely to protect against targeted attacks anyway.
Huh? The malware getting removed is not evidence that no harm occurred. Perhaps the malware stole something of importance. If that something was just power and network (e.g., for a DDoS farm), then it's of little importance, but if that something was keystrokes, then it could be a major importance. The user not knowing is a real problem.
Virus almost running on your PC is not a routine product feature that should be swept under the rug - at best it's bad security hygiene, at worst it's symptomatic of a targeted/ongoing compromise.