AOSP is open source, I've already said that. It doesn't care about my freedoms (so I don't care about its openness), but it's "open" as in OSI definition. That's true and I've never argued about that.
However, typical Android you get on smartphone (that's called "Android", too) is neither open nor free - it's usually completely proprietary bootloader, firmware and userspace, you won't have any source code for anything except for GPLed parts (i.e. Linux kernel). It just happens that those proprietary binaries were mostly built from unmodified AOSP code (but you can't really tell if code's modified or not), but this doesn't make them open.
You know you can change what's installed on your handset? Cyanogenmod supports a ton of phones... maybe next time you buy a handset, check they support it.
Ah, thanks for suggestions. Actually, I've had to buy a smartphone recently, and tried exactly what you suggested. Unfortunately it seems that Cyanogenmod has almost non-existent support for dual-SIM phones (at least nothing for what was available, and I was in a bit of hurry), and due to personal circumstances I needed this kind of hardware.
http://www.gnu.org/philosophy/free-sw.html
http://www.gnu.org/philosophy/free-software-even-more-import...
Regardless of whether most users know what to do with the source code, are they free to ask or hire a developer of their choice to study and modify it on their behalf? drdaeman's point, which seems inarguable to me, is that with most Android devices, the answer is no, because Sony/Samsung/Motorola are free to use AOSP code under the Apache license, but they don't pass that freedom on to the user.
This actually makes Android more attractive to Microsoft and generally increases the chance of a divergent, proprietary fork, which I believe Kindle already is.
That is why FSF keeps criticizing "Open Source". This nonsense is awful. Software freedom is extremely important to end-users. They might like to do something as simple as protect their privacy and turn off surveillance or uninstall bloatware! If Open Source isn't about those things at all (even though they do NOT require programming skills!), then we really need to keep focusing on software freedom for real and not your insulting interpretation of "Open Source"
Just because you've chosen to create your own ill-informed definition of what open means, doesn't make android any less open.