Meconium is a sign that your baby may be in distress. If they continue to be in distress they continue to poo in utero. This becomes a major problem for the baby as the meconium enters their lungs and they have major difficulties breathing (intensive care/death/long term lung problems). Because of this it is great they erred on the side of caution. If your baby had meconium aspiration then they would need more than an oxygen cylinder and a midwife.
I had the same thing as you. I got the syntocin drip which was horrid. His temp was low the next morning and spent a few hours in the nursery warming up- they didn't think skin to skin was enough?!?
It's all very frustrating I agree especially when it means you don't get the birth you want. My next child had no meconium problems.