I agree that letting kids chose what to study is a good thing but I think that's more for older kids for a number of reasons.

1 - they need some experience with the subject to know if they like it and it would be a shame if they gave up on maths or history entirely because of a bad impression at the very beginning stage when if they got to know the subject better they might love it

2 - young children if left to their own devices probably won't do the early childhood work they need to. Children mature as they age and I would argue it's abusive to give them responsibility for their decisions before they are old enough to make them properly

3 - society and the children themselves do need them to have a baseline level of knowledge in various subjects.