Illumos has a COCk, so already it has been subverted to the woke hate mob.
It really seems like OpenBSD is the only Unix OS left that doesn't have a COCk.
And perhaps macOS, but it's mixed source, and the base system (FreeBSD) has a COCk.

When it comes to non-Unix, TempleOS and FreeDOS seem to be the ones without a COCk.
Not sure about XFDOS (which if FreeDOS with a GUI), SoyceForge is just insanely hard to navigate through.