curl https://install.meteor.com | /bin/sh
This is not much different from running random .exe files that you find on the internet...
Have you ever made a .deb or .rpm, let alone a YUM or APT repository? The documentation is horrible. The .deb documentation mentions all kinds of abbreviations and obscure commands... fakeroot, autobuilder, pbuilder, dh_make, devscripts... good luck with that if you don't even use Debian as your primary OS. RPMs are slightly easier though by much. And this is only about generating the .debs/.rpms themselves. Good luck learning all the complex packaging rules and dependency specification rules.
What if you don't have a Mac, do you have to fork over $1500+ to buy one just so you can create a .pkg?
I'm not saying that's a justification. I'm just saying why people do it.