The core problem stems from the government's claim that the way to raise standards is to make children do high stakes, 'summative' testing. This is not testing to help children progress (known as 'formative'). It is a way of testing teachers and schools - test the child in order to measure the teacher's success in getting the child to know a particular amount of stuff.
It can only be done if it's supposedly valid for all children and all schools. This requires the knowledge in the test to be reduced to right/wrong answers.
If we reduce what children learn to this, it sets up a particular kind of model of 'how children learn' - that is learning without enquiry, investigation, interpretation, invention or co-operation.
It also sets up the idea that knowledge is not something you have a hand in making for yourself by engaging with other people. It is simply a matter of being a sponge and mugging it up. Ultimately, this is simply a lesson in obedience, not a lesson in how to learn, how to know, or how to understand.
We can ask: is this the kind of learning that we want our children to be involved in? is this the kind of learning that we want our children to think of as the most important on offer - because it's the 'high stakes' stuff? We can ask do we want knowledge to be reduced to this? And do we want to live in a world in which this is the main or dominant idea about knowledge and learning? Aren't we more than that? Better than that?