Germany requires the same (Homeschooling isn't allowed, except in very specific cases -> A child that cannot be transported/isn't mobile at all for example).
For me that is The Right Way. The same education for everyone. If the public education sucks, we need to improve that not work around the issue.
And .. the majority of reasons for homeschooling are plain invalid in my world (often based on religious ideas, claiming that the curriculum is containing 'forbidden'/'evil'/'wrong' stuff).
'Free society' doesn't imply the right to do everything. You cannot drink and drive. You're not allowed to beat your (very own, hey you made those!) children. For some, myself included, the requirement to send your kids to a 'real' school is a necessary thing and not Restricting The Freedom.
You're free to disagree (both in Sweden and Germany), but in that case you need to decide if that freedom is important enough to warrant a move - or you can try to lobby against the majority/the status quo. Ignoring the state and law (as the family seemed to have done) or calling it wrong won't help.