They do it because they don't know about org mode
Yes, I do in fact use Orgzly. For a very specific subset of notes it's fine. But for a long bit of documentation, no good editor exists on anything but a desktop / laptop. That is, nobody's reimplemented enough of Emacs on Android yet.
For typing, Termux's "extra keys row" makes ctrl and meta combinations possible with your favorite keyboard: https://wiki.termux.com/wiki/Touch_Keyboard
...or you can just use Hacker's Keyboard (but I find it too cramped).
Git also runs fine under termux if that's what you use to sync your org file.
"Long bit of documentation"? Isn't it the device that's not suited? I sure wouldn't want to do a lot of typing on a handheld device. Emacs shortcuts should be fun.
Don't get me wrong, I love org mode, but there is no real support on Android other that a damn-fine list-making app that uses a subset of org-mode format for its lists.