Indeed, if you boot a Solaris install disk in single-user mode it'll also give you root access without a password. In fact this is the official way to recover lost root passwords. Likewise, Linux too can be booted with a kernel parameter that gives you a root shell with no password required. You don't even need a CD on many boxes, I don't recall anyone making a big fuss over that.
Besides, if an attacker has physical access to the machine, all bets are off anyway. That's not really Microsoft's fault.
Shame on you for falling for this one, John.