I'd agree - from what I've read (and the look of what's in the refrigerator), the Shaoxing is aged, which develops flavors and color (like many Sherry - just not fino). Sake is not typically aged, hence why it is clear. Also, I can't find any reliable info about Shaoxing's abv, but sake is quite high - about 15-20%.
Edit: sake is not typically aged in containers that would impart flavors or colors, like oak barrels...