Also, (and this is just my personal opinion), but if my baby was not breathing when she came out and if nothing happened after a minute then I would want them to do anything absolutely possible to get her to breathe.
But leaving the cord to pulse gives baby time to transition to pulmonary respiration - baby is still receiving oxygen (to the brain and other organs) via the cord. If physiological third stage is followed, baby could have 20 min or more to do this - baby can also be worked on while still attached to the mother.
Interestingly, I understand that ambulances that attend unplanned births out of hospital know not to interfere with the cord and to leave it attached to avoid a second 'patient'.
Op, I'm so sorry it didn't go the way you hoped. I'd be sad too...
How did you come accross this MW? Was she independent or through a hospital scheme? Did she have much homebirth experience?