Because it's awful to use, counter-intuitive, and fucking breaks network connectivity all the time by switching private networks to public on a whim.
Fuck that piece of shit for that reason alone. I've seen it fuck domain controllers doing this, when "supposedly" it can't do this on a DC. Know what happens then? I can't RDP to the server from it's own local network.
This is such a problem we run a powershell script on a schedule to ensure the connections remain private.