I hate this stuff too - although of course it can help some women, and birth is a wonderful and natural experience for some women, no class or organisation should present it to pregnant women as if all they have to do is get their attitude right, breathe properly, etc. No wonder so many women are down on themselves after having to have a CS or even painkillers.
I was reading a thing about farmer and she has sheep who sometimes die in childbirth, cannot give birth without assistance, cannot bf. It's normal and no one blames the sheep for not trying hard enough or breathing right. They just find a solution to help.
It also makes me think of eyesight - we haven't evolved to all have perfect eyesight - a few people have no problems, many people need aids to see and some can't do it at all. But no one blames you if your eyes don't function perfectly.
Childbirth is similar – it does not go right in a significant amount of cases and that's part of what is "natural" for us, as a species, at the point we are at.
I had 2 C-sections, I don't feel bad about them (in fact I expected to need them because of family history) but the pressure from midwives to try for a "natural" birth ("we can just use forceps!") was horrendous - even when I had a BOOKED CS and went into labour early. There's also a sense of an opposition between MWs and doctors which is really unhelpful when they should be a team and prioritise what each woman needs, instead of an agenda.
I think it's an over-reaction and backlash against the previous tradition of birth being over-medicalised , but it fails to take account of the reality, and ends up making so many women feel like failures.