And now we see why Android never really was Linux.
Does it have a Linux kernel? Of course. But this isn't a free operating system.
Most of the problems are with the ease of modifications. Regular Linux based distro, with it's shared library model, masses of packages, and a proper packaging system, etc., will allow you fairly easily to just take any package, patch it however you like and just re-compile and install just the updated package. It's usually not a very hard process (well, Debian...) but there are distros where this is very simple, like Arch Linux, or Slackware.
I mean how do I just take some random Android phone and patch out something I don't like in one of the apps, or improve some behavior I don't like in one of the core libraries (like allow the fucking phone to be fucking woken up predictably by a background app, without some stupid mean-well logic trying to prevent predictable behavior, because waking up for 500ms every 5 minutes is "draing the battery too much" or some such nonsense)
There's usually not even a SW distribution, let alone a sane system for updating just one thing, without downloading 3 HDDs full of dev dependencies and re-building everything. Then HW is locked down, SW is locked down on purpose and just by sheer hostility to incremental individual small changes.
Whole ecosystem has to be designed around the FOSS ethos of giving the user access to code for purpose of them being reasonably able to actually do something with it to incrementally improve their experience, and not just to look at it pretty.
RHEL isn't Linux either then?