De or no de?

 I’m confused. The lesson states:

“To express lacking [something], you use:

manquer de or d' + [thing]

As you're literally saying I lack of [something], you never use partitive articles (du, de l', de la, des) here; i.e., Je manque du sucre.”           

So why not “Je manque de sucre?” The answer directly contradicts the Green highlighted guidance.