i mean, that sounds like a subjective distinction, but it lets you unlock the bootloader and then re-lock it with your own keys so eh..?

If you conceive a device to be shipped with a specific OS that's a completely different relationship with the developer than just giving the keys to the kingdom and wishing good luck, so I hardly think this is subjective

they used to publish a buildable AOSP tree for the device which is no longer the case