Vatican II in part stated that the rubrics ( the laws, or procedures, if you will) of the Mass were to be reviewed and modified.
Liturgical research and scholarship had been going on for a number of decades before Vatican Ii was called together, There were 2,000+ bishops gathered over several years in Rome, and part of what they wanted done was to make some changes as to how the Mass is celebrated based on that research.
And the discussion (some times a shouting match) has been continuing on to some extent ever since. One bishop recently referred to the EF as “baroque”. Baroque generally is taken to mean redundancy, and elaborate, and with an abundance of details, People who prefer the EF often take offense at such descriptions. While it is accurate, too much of the discussion wanders into emotional territory, a place where there are no winners.
The OF was introduced, often in dioceses without any real preparation for the amount of change or any description of why the changes were made, and in all too many circumstances was subject to abuse. Some of that is similar to a child who has been under strict parenting rules; turns 18 and goes off to college and goes hog wild. Most of the chaos was in the 1970s and the 1980s, and by the 1990s things started to settle down. In discussions (shouting matches) of it, it is often made to appear that abuse was everywhere. It wasn’t, which is not to excuse any of it, but hyperbole reigns supreme in too many of the recountings.
In any event, all 5 Popes have said the OF and continue to do so. The EF is said in very few parishes (for example, in the US, around 2% of parishes may celebrate the EF; some are EF parishes, and some celebrate the EF either at one Mass on Sunday, or infrequently.
Just curious: in what part of Holland are you? My family is from Reek primarily, southwest of Nijmegan. But that goes back to my great grandparents.