Beaming the light back is a reference to completely separate items left on the moon: 6 reflectors (3 Apollo, 2 lunokhod, and 1 chandrayaan). It's a grid of reflector cells like a huge, metal version of the reflectors you see on cars and bicycles. By measuring the time between shining the laser and recording it's return, scientists can measure the exact distance to the moon and how it's changing - both it's orbital wobble and it's drift.

So you're correct, there's no desire to have the laser bounce of the solar panels. The comment was just citing the existence of a light source powerful enough to reach the moon from earth.