Interesting how that was achieved. Most popular Linux distributions are very hard to install without python3 an perl5. LSB https://refspecs.linuxfoundation.org/lsb.shtml defines them as standard.

Maybe not so hard as you might think. On my openSUSE desktop, uninstalling python3 would remove only calibre and virt-manager. Most of my server/container/vm installs don't have any python version. Perl isn't much harder to get rid of depending on the use case, for example some development stuff uses it.

I'm also not sure distros generally care about LSB. Debian dropped it years ago and did any distro even bother to implement it correctly?

I don't get all these arguments. You would really prefer to use hard-to-check shell script to simply installing system python package if it isn't installed already?

You said distros can't install without python and perl, my argument is the opposite. Shell scripts aren't in the picture.

Why would I want a system level python install?

Because it allows for scripting infrastructure with far fewer obfuscated hacks than bash/awk. And if you use system python, vulnerabilities are more likely to get patched by distribution vendor. Your homebrewn json parsing regexes won't.