I teach primary school children (aged 10 and 11) once a week. I think the author is mistaken and using a lot of assumptions to justify a very bigoted position.
Firstly, most children are not capable of making good choices for themselves. This is essentially why we teach them, if they came out of the ground fully aware and able to rationalise there would be no need for schools. My direct experience is that some children are quite self directed and can be left to pursue their interests and work around topics in their own way. Most children however find a lack of direction quite daunting and will end up not working at all if they are not given quite clear instructions.
Secondly, allowing each child to pursue their education in their own preferred mode is unreasonable because of class sizes. I have found it very difficult to support more than 5 or so children who are all doing different things, even if they are focusing on a common subject and broadly similar tasks. The only way for a teacher to reasonably teach a class of 20 to 30 or more is to give them all the same work and teach them all in more or less the same way.
The author makes the mistake of assuming his teachers were stupid or mean. Whenever you find yourself assuming this about other people you should take a step back, because there are very few individuals, and certainly no broad categories of people who are actually like this.