The problem is people delete glibc and are surprised when glibc features are missing.

The only point I'm making is: Linux does not require glibc.

Users and their programs usually do require glibc but that's their choice. It's not mandated. People could theoretically rewrite the entire Linux user space in pure freestanding Rust if they wanted to.

Name Service Switch is just a solution to a problem. There's no law that says Linux systems must have that system. Programs that depend on it will break if it's not there but that's not the fault of Linux.