> That would be every day that I run apt-get, pkg add, brew install, or download a random .exe/.dmg to update my machine.
Everything except that last part, are not "random strangers on the internet", those are maintainers who maintain the registry/repository you've chosen to use. And when you use those, they use "mirrors" hosted on their own infrastructure.
AUR is a very different thing from this, where essentially anyone, at any time, can become a "mirror" and host whatever code they want, with zero review.
I obviously don't review stuff when I use pacman and official Arch package repositories, because again, those aren't "Wild west of random binaries", like the AUR.