Why doesn't the sun reflect off Earth's oceans from space like a billiard ball?

The fact that the ocean is proportionally smooth doesn't matter -- when a light wave with wavelength ~500 nm hits the ocean, all it knows is that it's running into huge, 60 foot tall irregularities. It doesn't care if these waves are small compared to the rest of the earth. I mean, how would it even know?

For specular reflection, you need smoothless relative to the wavelength, not relative to something else.