This is 13 lines of Bash plus GPG which is available ~everywhere and a pretty lowish level Linux dependency. SOPS is +20KLOC of Go with support for cloud KMS etc etc. I think you got your mystery meat analogy backwards.
I’ve used a Linux desktop for my entire adult life, and I’m pretty sure GPG has never been bundled directly with my environment. I used to install it directly, but I haven’t needed that in years either since everything I needed GPG for (= git) supports SSH signing instead.
Perl is horrible, but for one-liners it's strictly less horrible than either sed or awk, which people still use because they are less horrible than pure Bourne shell for some common tasks.