It doesn't, it uses correct contextual capitalisation. "De" is the definite article in Dutch, and in a full name the correct capitalisation is written using low

It doesn't, it uses correct contextual capitalisation. "De" is the definite article in Dutch, and in a full name the correct capitalisation is written using lowercase ("Hans de Zwart"). However, when used in isolation it needs to be capitalised so as to differentiate it from "an incorrectly capitalised noun/adjective following the definite article". If English had surnames that started with "the ...", the same rule would be applied, where "Jason the Bouvier" would be the correct full name spelling, but in isolated context, such as "According to The Bouvier, this policy has [...]", capitalisation should be used to make it clear that this is expressly not the definite article.