Nobody seems to have an issue with checking this for apps -- it's a good security feature to protect from malware, right? And which everyone knows about? And it only happens the first time you run something, so it's not a performance issue in everday usage.
And the article even states that there seems to be a valid reason for checking shell scripts, because they can be used to compile malware.
The original complaint was about slowness, but how often do you run something for the first time? The only scenario in which I can imagine this would become a practical peformance problem is if, somehow, you have an app that spawns new shell scripts all day long to execute, every few seconds, and a really flaky internet connection. Or new shell scripts hundreds of times a second, even with a good internet connection.
Is that something anyone ever needs to do? Programs can run shell commands directly, without a file, so it seems unlikely. Also, another comment here suggests that even if a shell script is modified, it isn't re-verified, so there would seem to be a trivial workaround anyways.
Or is the issue just that this is undocumented behavior? Or what am I missing here?