What causes male pattern baldness?

[gmonasco]

I was reading the Wikipedia article on androgenic alopecia (i.e., male pattern baldness), and it contains the following passage about the causes of MPB:

Male pattern baldness is caused by a genetic sensitivity of hair follicles to DHT, which causes them to shrink or "miniaturize" when exposed to it. This shortens their lifespan and prevents them from producing hair normally.

Recently the existing theories have been challenged on the ground that while the androgens in question are responsible for hair growth on the face and all over the body of men, hair loss is only occurring at the top of the scalp. In a new theory it has been propounded that androgenic alopecia is a counterproductive outcome of the anabolic effect of androgens. It explains how hormonal changes in males lead to structural changes in skin and scalp which in turn cause hair loss.

I'm not sure I understand what the second paragraph is trying to say. Can anyone explain it in simpler terms? It sounds like some are maintaining that DHT doesn't actually cause MPB because the only hair loss in MPB is at the top of the scalp rather than all over the body, and it's actually some other hormonal changes that are causing MPB.