That's just ignorant.
Oh the irony... I can't work it out either but then I haven't been brought up with the system.
It's 4691 * 10^3 meters, 4691 * 10^5 centimeters and 4691 * 10^6 millimeters. So what's it in imperial? Surely you were brought up with one system or the other... Degrees isn't metric yet there's no uproar about that.
That's because you're flat out wrong. Then we have radians. This is the arguement in reverse.. radians is akin to metric system (mathematically superior, whatever that means) and degrees is akin to imperial (easier to use).
Wrong again. By the arguments presented here in favor of the imperial system, radians are the imperial analog. It has nothing to do with being "mathematically superior", although radians are a less arbitrary measurement than other ways of describing an angle (or more accurately, the length of a circumference). Radians (much like the imperial system) is simply easier to divide up into nice "complete" numbers. A circle is 2*Pi. Half a circle is Pi. A quarter of a circle is Pi/2. An eighth of a circle is Pi/4 and so on.