Sure, Android is open source. If you count half of the OS that hasn't been updated in literally years (last I checked, the AOSP music player is still exactly the same as it was in Android 2.3), but instead has been made into proprietary Google (tm) (r) (c) apps, as open source. Don't confuse Android with AOSP, and don't think AOSP is even remotely up to date or usable without having to add anything to it.

How do you edit your Android lockscreen? How do you use a different UI in Android? How do you even do anything in Android without having to resort to security holes to install superuser?

If you complain about one thing being **** in comparison with something else, at least first make sure that other thing isn't just as ****, if not more.