Meanwhile the XZ backdoor was found in Sid, Arch and pre-releases of Fedora and openSuse. It never actually made it into any numbered release of Fedora, openSuse, Ubuntu, Debian, Red Hat or Suse distro. It's actually a pretty big win and the system worked as intended.
Open source and Linux are doing just fine security-wise.
Also, none of this has anything to do with using offline tools like a word processor to make documents.