In addition to vonbrand's answer, let's not forget a major contribution to the GNU/Linux OS is that a lot of the GNU stuff was already there, already functional as a whole ecosystem and freely available under an open source license when the Linux (kernel) project started.
One should not forget either what the original GNU project goal was, i.e. building a free Unix clone. Unix was and is even more nowadays a set of specifications containing all the API, commands and functionalities expected from an operating system to comply. This standard is extremely helpful for developers to build portable applications.
The GNU libc and the GNU coreutils/binutils are precisely providing these APIs and commands to most OSes based on the Linux kernel. They form the foundation on the top of which everything else can be built.
Whatever their usefulness and their complexity, the remaining components are optional and not specified by the Unix standards so are technically not part of Unix operating systems and their clones.
That's the reason I believe there is no much point to call a Linux distribution Linux/GNU/TeX/X11/Python/ISC/Apache/and so on as only Gnu and Linux form the core which provides the common foundation expected by all the Unix/Linux ecosystem.
TEX/X11/Gnome/KDE/Perl/Python/ISC/Apache/Tomcat/LibreOffice/Mozilla/Chromium/Whatever, as useful as they might be, are not part of Unix/Linux.