I can only assume that Andy Kim wasn't thinking about librations when he sang "Rock me gently".
Libration is derived from the Latin, which means scales. There are many types of scales but one of most accurate for weighing is the balance scale. Nowadays, the the balance scale is mostly seen as a blindfolded maiden holding in one hand the "scales of justice"
Although "Justice is blind", there are many examples were cases are miscarried.