OP, I know exactly how you feel but stupidly it took me till after the birth to figure it out.
On certain websites, especially British, there is enormous focus on 'a lovely, empowering, natural birth' helped by all the preparations you have done and your affirmations, dim lights, candles, whatever. Hypno CDs talk as someone mentioned, only about pressure, not pain. There is a dog-whistle of not outright condemnation of pain relief as leading to an inferior birth, even an inferior baby and mother. And it is all so carefully phrased that while the message is loud and clear that real women don't do pain relief and that it is your special level of preparation and doing 'the right thing' leads to success, as defined by natural, drug-free vagunal birth.
You have done so well to spot that it is BS. All of it. Labour is and always has been regarded as some of the most painful sensations in the human body. The nerve endings that transmit labour pain, and the receptors in the brain that receive them, are exactly the same as any other pain. Physiologically, it is in no way different. Many religions see labour pain as a punishment from an all-powerful vindictive God - don't you think that would sure as heck hurt?
It infuriates me that natural birth movements try to persuade women that none of this is true. And when you realize after the fact, you will see a lot of comments like those earlier in the thread that "nobody ever promised it would be easy or pain-free" when in fact that is the clear implication they intended you to take from their messaging. And then the victim blaming - of course it hurt if you were tense, if you had feared less, it wouldn't have hurt. It's all nonsense.
And then there is the repeated encouragement to disregard medical advice in favoyr if positive thinking. How many people have told the OP that growth scans can be inaccurate and so her baby could be a pound smaller? But how many of these said that the converse is also true, the scan could be out in the other direction by they same margin of error and the baby a pound even bigger?
I really dislike that the natural birth movement is so dismissive of women's pain, so quick to attempt to isolate them from medical experts in Favour of homespun woo. Congratulations on seeing through it.
For what it is worth, I had an induction, epidural, ventouse and episiotomy plus I now have stress incontinence as a result, and for a brief time felt like a failure as a mother. Now that I can see through the web of nonsense, I feel anger. Women should always be listened to, should have their pain acknowledged and treated exactly as they wish and should not be subject to these horrid competitive societal pressures.
Best of luck. My one piece of advice - epidural a are amazing