The point is that when you use a distro, you trust that distro and its maintainers. If you use the package they build for you, then you rely on this trust.
Now if you use a random script from the internet, then you don't give your distro maintainers a chance to actually review the package and instead you blindly trust this script. Arguably you increase your attack surface.
Also a system package manager checks the packages (there is signatures and stuff), whereas piping a script to curl doesn't do that at all. So if the server is compromised, you just execute random code. It's harder to compromise the system package manager.
Which is not the same thing as a signature on the package, is it?
> Distro maintainers in general do not audit the code they package.
First, it depends on the distro. Second, they certainly do at least some kind of due diligence before packaging a new project. So there is some amount of selection (which you don't find in npm, cargo or pypi).
Now if you use a random script from the internet, then you don't give your distro maintainers a chance to actually review the package and instead you blindly trust this script. Arguably you increase your attack surface.
Also a system package manager checks the packages (there is signatures and stuff), whereas piping a script to curl doesn't do that at all. So if the server is compromised, you just execute random code. It's harder to compromise the system package manager.