Redling - I think maybe you've misunderstood what people mean when they talk about people advocating for them if you think it means disagreeing with medical advice about your/your baby's safety.
For example: in my first labour I was told that I should have a routine period of continuous monitoring for about half an hour on admission (though was left for closer to an hour. Belts went on, mw wandered off). Told to lie down and have belt strapped up. I was in agony on my back. This happened a few times. E.g. when they broke my waters, half an hour on my back to check that my baby was happy. It was only afterwards that I discovered that it would have been perfectly possible to do the monitoring in the kneeling up position that I found far more comfortable. Just a bit more bother for the midwife, and I might have needed to lie down if that position didn't get a decent reading. Or in some of the situations, she could have used the handheld Doppler - she basically just didn't want to crouch down and was keen to have a print out for her file.
I was too exhausted and in too much pain to argue, but I really could have done with an advocate who, after the first time, said "Penguins is finding it really difficult to be in this position. Is there any way we can do it differently". By my second and third births, DH was well briefed to look out for things I was finding particularly hard going and find out if there were ways to make them better.
Or another example, lots of units will have expectations about how fast you 'should' progress. However, if everyone is ok and wants to wait, you don't need to necessarily go down the route of augmenting the labour. If you are too 'in the zone' or in too much pain to hold a discussion on that, having your DH 'advocate' for you on that can be useful - whether you eventually decide to hold off or whether there are strong reasons for augmenting.
In my third labour, I had an amazing, amazing midwife .I can't praise her enough. I certainly didn't need an advocate. But, like any profession, there are better and worse mw's (and more and less observant and/or compassionate ones).