I actually would not consider the selfishness evil, because it is purely natural. Of course wild animals, who can ALSO distinguish between right and wrong (I believe) fight to survive -- I would not consider this evil.
Humans not only seem to have the will to survive, but the will to survive lavishly, clouded from the authentic by the artificial. The metaphoric "cloud" here would be civilization; it provides convenience for nearly everyone, keeping those in it from authentic life.
This, however, is not so bad at all. I would barely consider it evil. There is something however that is at the root of alot of evil...
Are ya ready for this?
It's Peace. The desire for peace creates alot of destruction and evil. I would not buy into the "Renunciation of the will" literally, but take it on a bigger scale: the will to have peace is what causes dehumanization and artificial destruction. What can we do? Accept that there is never complete peace -- I think, the day that there is, is the day that the universe ends.
It is civilization that is truly evil and artificial - it is meant to be the facilitator of peace and the ensurer of order.