It is not my business or your business but it is the child's business. The child will grow up to be a delusional sheep, and the child's rights are violated when you teach him/her utter crap as science.
The child is best served in a competitive educational marketplace, in which theories and ideas are taught based on competitive merit instead of diktat.
I'm not going to get deeply involved in this chat - as we're now pretty off-topic, but
The marketplace you suggest effectively peddles a lie on the unsuspecting child. The lie is that they are receiving an education that is roughly equivalent to their peers on a national or global level.
Let them send their kids to whatever extra-curricular classes tickle their fancy - but you can't expect a madrassa or fundamentalist christian school to give a proper treatment of modern science *yet the 'customers' (ignorant parents & naive kids) are often unaware of this*.
The theories and ideas which are in the curriculum have already won on competitive merit in the scientific peer-review process.
Regardless of what baloney people want to teach their kids on the sidelines - they shouldn't be able to pretend that their local preaching institution is giving an equivalent and relevant education.
I agree with evoorhees here...you might not like what someone else is teaching their kids, but they have to be free to teach it too them. This is where crazy ideas (like the world is round) come from. If we allow a monoculture around education to develop, we all lose. In a private system, the vast majority of people will put their kids through some accredited and conformist education because that's the path of least resistance to developing the tools needed to be successful. But we need those alternative perspectives as well...every once in a while, they yield something that truly changes the world for the better.
Actually, no. You should not be free to teach your kids whatever you wish, because your child's education isn't about you, it's about your child.
The crazy idea that the world is round was a scientific determination made by the ancient Greeks (among others) well before the prevalent, Christian institutions of the early and middle ages decided the Earth was flat. It was the secular, non-religious sectors that succeeded in making the crazy idea the paradigm... but the point is that the idea was only crazy to the institutions of religious Europe, not the Greeks, not the Chinese, not most of the Arab world and so on.
The alternative perspectives you speak of can and should be pursued outside of the education system. The operating notion here is that of the rights of the child, not of the parent. Every child has a right to the most adequate education possible. To suggest that teaching children the world is about 6,000 years old is adequate is ridiculous. That child, indoctrinated into believing the world is 6,000 years old, has had his or her rights trampled on.
We, as a society, defend the rights of children not just because it's just, but also because it's self-serving. Children, as it happens, typically grow into adults. And it seems to benefit us as a society to have adults whose rights were not interfered with while they were children. Funny how that works out.
In fact, at present, every child in North America is suffering because the quality of science education in primary and secondary schools, particularly in the United States, is simply appalling.