Way to a good school in Netherlands

In The Netherlands children are tested in the 6th grade, secondary education is divided into several levels of education (4 to be precise). More and more parents hire people to train their children for these tests which defeats the purpose of testing and undermined the effectiveness of the tests. I’ve heard from teachers in secondary schools that it is devastating for children to be placed back when it turns out that they are in a level that they are not suited for.
Parents who impose training for tests on their children are harming them. In my personal opinion children deserve to be in a school that makes them feel confident and happy about who they are. A childhood filled with working terribly hard (and structurally feeling as if you are failing) and constantly being implored by anxious parents that you have to be different can’t be a secure foundation for a happy adulthood. Parents need to identify what they fear and work on that instead of manipulating their children in this way.