The obvious issue of equating prevailing mores with morality is discussed to death in the comments.

Except, as far as I can tell, he is proposing using Pagerank (or some modification -- an update proposes using temporal info per Luca's suggestion) as a way to classify into good and bad guys that accords with our intuitions. This does not work (for fairly obvious reasons, which I am sure Scott is aware of, so I am not sure why he decided to talk about morality at all).

re: "why are people so negative:" this is how analytic philosophy works! Someone proposes a defensible point, and then everyone else shoots it full of holes.