Just a quick point of identity on which I believe you're absolutely wrong. You wrote:
"Some parents feel a strong adherence to an ethnic or religious group and want their kids to feel it too. This usually requires two different kinds of lying: the first is to tell the child that he or she is an X, and the second is whatever specific lies Xes differentiate themselves by believing."
I won't try to argue with you about religion, but it also denies the existence of ethnic identity.
Here's a counter-example: Black parents can tell their kids that they (the kids) are black, and that's not a lie (unless you deny the existence of ethnicity or ethnic identity), and there is no need to tell any further lies lies by which black people would "differentiate themselves" (even though such lies certainly exist). Skin color and heritage are two very real things that are very relevant for many people.
"Some parents feel a strong adherence to an ethnic or religious group and want their kids to feel it too. This usually requires two different kinds of lying: the first is to tell the child that he or she is an X, and the second is whatever specific lies Xes differentiate themselves by believing."
I won't try to argue with you about religion, but it also denies the existence of ethnic identity.
Here's a counter-example: Black parents can tell their kids that they (the kids) are black, and that's not a lie (unless you deny the existence of ethnicity or ethnic identity), and there is no need to tell any further lies lies by which black people would "differentiate themselves" (even though such lies certainly exist). Skin color and heritage are two very real things that are very relevant for many people.