MacOS Catalina: Slow by Design?

Okay, I've tried this test on my MacBook Air 2020 several times, first by saving the "echo Hello" shell script in an editor and then, because I wasn't getting the results the author experienced, trying again exactly as he wrote it. Essentially the same result:

    airyote% echo $'#!/bin/sh\necho Hello' > /tmp/test.sh
    airyote% chmod a+x /tmp/test.sh
    airyote% time /tmp/test.sh && time /tmp/test.sh
    Hello
    /tmp/test.sh  0.00s user 0.00s system 74% cpu 0.009 total
    Hello
    /tmp/test.sh  0.00s user 0.00s system 75% cpu 0.007 total

Is it possible that Allan Odgaard, as good a programmer as he unquestionably is, has something configured suboptimally on his end? Because it just strikes me as super unlikely that Apple has modified all the Unix shells on macOS to send shell scripts off to be notarized. (From what I've read, while shell scripts can be signed, they can't be notarized, and Gatekeeper is not invoked when you run a shell script in Terminal -- although it is invoked if you launch a "quaurantined" shell script from Finder on the first run, but it treats the shell script as an "executable document." This is the way this has worked for years, as I can find references to it in books from 2014.)

I have my complaints with macOS Catalina, and I know that Apple's "tighten all the screws" approach to security is anathema to a lot of developers (and if there was a big switch that I could click to disable it all, I probably would), but I'm using Macs running Catalina every day and I gotta admit, they just don't seem to be the dystopian, unlivable hellscape HN keeps telling me they are. At least off the top of my head, I can't think of anything I was doing on my Macs ten years ago that I can't do on my Macs today. ("Yes, but doing it today requires an extra step on the first run that it didn't used to" may be inconvenient, but that's not the same thing as an inability to perform a function -- and an awful lot of complaints about modern Macs seem to be "the security makes this less convenient." There's an argument to be had about whether Catalina's security model strikes the right balance, of course.)

10 to one says this is because you've run something calling /bin/sh before.

if he switched the /bin/sh out to /bin/zsh or /bin/bash which ever his default shell was, he wouldn't have seen the first delay.