Switch with 2 Hot?

Greetings, We have a 'play' room for the kids in the basement. The switch controlling the lights was mounted about 66in high, and the kids couldn't reach it. I went to move the switch down to a more reasonable height, and ran into something I hadn't seen before... It is a single pole, on/off switch. Two contact screws, plus the ground. There are two romex cables entering the box - both hot (black) wires are connected to the switch, and the neutral (white) wires are wire nutted together. Is this correct? I expected to see a hot and neutral connected to the switch. Is this because there are two cables coming in? I did move the switch down (used the old box as a junction with a blank plate, and a new box for the switch. I wired it exactly the same - junctioned the two cables, ran it to the new box, and wired it the same. Works... Thanks!