...and? I think I see the point that you're trying to make, but I don't think that it's pertinent to the discussion. A tablet is still a "personal computer" (solely as a descriptive term) without the keyboard, and regardless of Apple marketing. But it's not a "personal computer", in the same sense that common usage of that word doesn't include (most) tablets, smartphones, PDAs, programmable calculators, etc.
But, we digress. Tell me again how it's reasonable that hardware that will run OSes 1, 2, and 3 shouldn't be allowed to run OS 1, because the hardware doesn't have a fruit sticker on the side.
Old hardware was inherently incompatible software-wise, due to widely varying CPU and system architectures. ARM and MIPS hardware today somewhat mirrors that on a device-by-device level; every model has different interconnections between its components and often different mixes of components connected in. Luckily, we've got OSes that provide relatively robust hardware abstraction layers, so that the same software package from my 2010 device is highly likely to run on my 2016 device. I think that strengthens my argument: when even widely varied hardware isn't much of a barrier to software interoperability, why should we be satisfied with legal limitations?
And anyhow, the point was software development. Going into the definition of what is and isn't a PC is a bunch of BS semantics. Let's drill down to the devices that are pertinent to the discussion: The set of devices that are technically capable of native (as opposed to web) OSX and iOS development, and the set of devices that are legally capable of the same. Those are what the discussion is about.