The linux kernel unfortunately does not follow unix philosophy.

It would be better in various ways if the linux kernel used a micro kernel architecture following the unix philosophy, something Torwalds acknowledged in the past.

Philosophical ideas being lost does not mean they’re outdated.

And that is bad?

All 3 systems use openssl and get attacked using Heartbleed.

(And even if they don’t reuse even a single piece of code, attackers can still just use multiple exploits.)

Adding a little to the other comment: Nix packages are fully reproducible, so you can verify they’re built from the source they’re claimed to be. That makes package distribution more secure. (E.g. Debian could add malicious code to some packages before compiling them, and you’d never know. Not saying they do that, but they’re able to.)