Explanation for newbies: The GNU/Linux copypasta is an argument made by Richard Stallman that the operating system should be referred to as "GNU/Linux" or "GNU+Linux" because linux is just the kernel and what makes it useful are the various GNU programs and libraries like coreutils and glibc.
Alpine Linux is a linux distribution that ships without any GNU software (though it can be installed using the package manager).
And that's why Alpine should be considered harmful. Copyleft is important, folks! musl and BusyBox are just ways to facilitate even more enshittification, Tivoization, and other corporate abuse than the GPLv2 kernel already does by itself.
Huh, good point, I never stopped to consider what licenses are behind Alpine.
I agree with your point that pushover licenses should not be the way forward (I personally license all of my major projects with GPLv3 only), but I'll still keep using alpine because I like it from a technical standpoint.
TL;DR: "Tivoization" means giving you the source code for the firmware of a particular device, but using DRM to prevent you from actually being able to make changes and run that modified code on the device.
Alpine and its components are fully open source, you can make whatever changes you want to them.
Who is "you?" That's the important question.
There's always this big debate about whether GPL or BSD licensing provides "more freedom," but that's the wrong way to look at it. The correct way to look at it is that copyleft licenses provide freedom for end users by prohibiting developers from obstructing their freedom, while permissive licenses provide freedom for developers by permitting them to restrict access to the code for downstream users.
Using permissive licenses in Alpine doesn't make Alpine itself not "fully open source," but it does mean that Alpine helps facilitate non-Free downstream uses. In other words, somebody could take Alpine, customize it for a device, and then sell that device to the public without making any code available except for a kernel that they wouldn't even be able to use on said device because of DRM. I'm not okay with that.
Their statement is that Alpine is designed such that it is friendlier to corporations who want to lock down their devices and prevent you from modifying them.
You cannot use coreutils and have a DRM locked down device.
You can use Alpine w/ musl + busybox and make a DRM locked down device
Alpine's licensing favors large corporation's rights in preventing the user from modifying their device
Operating systems using coreutils favor the end user's rights
... Alpine is designed to be friendly to corporations who want to lock down their devices and prevent you from modifying them.
"Designed to" assumes intent. Alpine is absolutely designed to be Small, Simple, and Secure. Using busybox instead of the GNU coreutils is a means to this end. Using musl instead of glibc is a means to this end.
On the about page they list why they use these tools. The licensing is not listed at all.