Everytime someone calls their system a Linux based OS and not GNU/Linux based OS downplays the work he put in.
Absolutely, and the fact that people didn’t adopt it creates confusion, some people claim Android is also Linux, which you can argue, but it’s definitely NOT GNU/Linux, and it’s definitely NOT a free desktop OS as defined by freedesktop.org either. There’s a huge difference.
Especially since Android generally means Android with Google apps, and not AOSP. AOSP is open source, but Android with Google apps is not.