All due respect, but you don't seem to understand the full issue here.
This person bought a simlock-free iPhone, this means the device is not connected by any business relationship to any carrier and should work to it's full potential with any carrier, that is why it ships out without a simlock.
This is the reason people take out up to double the price to get a simlock-free device.
Whether Apple actually blocked it or simply didn't enable it, I have no Idea, what I do know is that it either way it should be fixed.
Now in response the part where you say: "If you want full functionality, use a supported carrier." I'm only going to add this:
The only supported carrier by Apple in Belgium is Mobistar, and guess what? They do not have LTE yet.
I love Apple products, but when you buy a device for double it's price, you expect it to work at it's full potential. As it should.