Coming from a Linux background, this seems awful weird to me. Unlike Linux, where root login is denied by default in SSHd configuration, Windows users in Administrator group are allowed to login by default via RDP.
I believe it would make more sense, to follow the principle of least privileges and defense-in-stages. Instead of exposing the administrator account for remote logins, it makes more sense to allow ONLY non-admin accounts so that, even if there are any breaches, it is possibly contained.
So, what could possibly be the reason behind this decision of exposing Admin accounts by default?