I get you now....
Well, the benefits of being born vaginally are many, as you saw in the article. Yes, squeezing fluid out of the lungs (not just mouth and nose) is one of em--babies practice breathing in utero, so tend to have some amniotic fluid in their lungs at term. This lack of being squeezed out while in the canal, is why so many csec babies have 'wet lungs' and get respiratory help after birth.
Maybe you could google the topic... I can name many of the benefits physically, chemically, emotionally, but it would be a post as long as the article you mentioned! I was hoping you had some sort of access to it, so I would not have to write it all down myself, for clients, too bad. But, as I am in process of preparing a binder full of things for clients, I may just get around to writing it eventually...and then I'll post a link here.