The problem is the equation of any sort of religious teaching with "indoctrination" and "brainwashing".
In fact, several posters (including myself) have been pretty explicit in making a distinction here.
Those words are meant to imply something above and beyond normal behavior.
While the actual frequency isn't particularly relevant, I'd say its closer to the norm than the exception, at least in certain areas and with respect to certain religions (i.e. read: Christianity, rural United States, Islam, various places, etc.)
Now, you guys are all perfectly free to water down the term, and utilize it for the average family that takes their kid to church and has them pray before going to bed, but you shouldn't expect everyone to agree with your agenda-laden redefinition.
If the shoe fits... People who have themselves either received the sort of questionable religious upbringing we're talking about, or have/are/are planning on raising their own children in such a fashion, I'd imagine there will be an emotional reaction to the negative connotations of either word- ergo the sort of semantic quibbling and attempts at shifting the conversation we've seen from several posters on this thread.
As for me, I'll continue to reserve the terms "brainwashing" and "indoctrination" for cases that truly call for it-- for exceptional occurrences, and not normal child-rearing.
Again, my point, and what I take to be the OP's point, still stands regardless of the frequency of the religious indoctrination of children- but I'd say you are seriously underestimating the prevalence of the type of parenting in question. In many areas of the United States, in the rural south and midwest in particular, religious education is presented to children from an extremely young age in an authoritative, matter-of-fact, and indisputable manner, with content that induces fear and guilt via teachings about retribution in the afterlife, the concept of sin (a concept no child should be burdened with at all), and so on. There's really no way to sugarcoat it; this is indoctrination in every sense of the word, and there's certainly nothing inappropriate about calling it brainwashing either (semantic quibbles aside). Hell, some evangelical Christian leaders openly admit their trying to "recruit" (i.e. indoctrinate) as many children, at as early an age, as possible, as if they are trying to build an army (see the documentary
Jesus Camp- very creepy).
Now, once again bracketing how common we think this behavior is, the question of whether it is unethical isn't even really open- if you have trouble seeing whats wrong with this, then you have larger problems. But I think that, in Christian households in the US, it is not as rare as some here would have us believe- I'd imagine there's a spectrum, and that there are large regions where most people are going to fall
somewhere on that spectrum of religious indoctrination. And if it happens once, or 500,000 times, its still too many.