This period is specified in the Dutch Civil Code .
The General Data Protection Regulation (GDPR) must be followed for processing and publishing data from living persons. This law is about the protection of living persons, so it applies "briefly through the corner" that the deceased have no privacy.
The above two laws do not have to be confused! The publication times of the Dutch Civil Registry do not follow from the privacy legislation and for the publication of data of deceased persons they do not have to be born more than 100 years ago.
The term of publication of the documents of the Dutch Civil Registry may have been drawn up with privacy in mind, although people who are older than 100 years see their birth certificate being made public while they are entitled to privacy according to the GDPR...