Well please excuse my German stubbornness... The drywall anchors (thanks @stevehobbes@lemm.ee for the word) I know and often installed were certified up to 40 kilogram - per anchor (single layer drywall, one anchor per meter as a rule of thumb). A rack full of stuff like in the picture won't have more than 50 kilogram load (static load - please tell your kids not to climb onto the shelves) so two such anchors would have handled that easily, and there's plenty of room to install more than two.

I understand that other parts of the world live up to other standards.