I think it's a combination of a couple of things:

1) People are generally ignorant about birth, apart from what they see on TV. It's not like we live in communities where we see/hear a woman labouring regularly, so our information comes from "entertainment" sources. Mostly American rubbish too.

2) People love drama and seeing others suffer. Just look at the casting for reality TV shows - they combine people who will generally be nasty to each other and provide entertainment to the viewers, who can then feel smug and superior for an hour or so. So if we expect people to suffer, we generally feel ripped off if they don't. That probably doubles for those who have suffered through birth - they dont want to hear about an alternative. It threatens them.

From what I can see, the whole birth and parenting industry is generally geared to make women compete and put each other down. Anything that rocks that status quo is a threat that must be squished into the ground before civilisation collapses.

Stop being so bloody radical, lie back, take the drugs and do what you're told! *sarcasm*