As Biddle says, his argument is one that should not have to be made. I have made this argument myself many times and have tried to operate on it while arguing points on this blog. I left the following comment, which might be moderated out of existence:
For those wondering, the bullet of the four viewpoints that Biddle suggests that Ayn Rand may have been wrong about that I would not necessarily agree with was the one in which she asserts that a child has a duty to his parents. This is not a simple matter. There are contexts in which a child has a duty to a parent and a parent has a duty to his child. The parent-child relationship is very different than the relationships between adults. It is common for Objectivists to say that children do not have rights. This is another matter on which I take exception. A child has a right to be allowed to take actions that develop his potential to become a rational individualist. This is not to say that a child has the right to demand that someone educate him. What he has a right to is that no one be allowed to prevent him from trying to educate himself. A child's rights are very different than those of an adult, but they do have rights. Generally, these rights are a subset of adult rights. It is the legitimate duty of a parent, as it is of a government with respect to adult rights, to see that the rights of his children are protected from force by others. So, if a government forces a child to attend a government-run school where the child cannot appropriately pursue his development as a rational individualist, it is the duty of the parent to oppose that government requirement.