Cooperation, mutual aid, these are principles that life on earth has found to be beneficial.
Those things are not incompatible with selfishness. If I'm pursuing my own self-interest, I might quite rightly choose to cooperate with my peers for mutual benefit.
Conversely, if I don't pursue my own self-interest, what exactly is the point of living at all? It's not like intelligent life serves any objective purpose or end, other than that which we individuals imbue it with.
We just seem to use a shitty definition of selfishness these days.
That's English for you, where every word seems to be overloaded with about a dozen different meanings...
The problem is, selfishness (in the negative sense) and what I would call selfishness are actually related in a sense, which makes it easy for people to slip in and out of using either meaning in conversation, and everybody winds up arguing for no reason.
Those things are not incompatible with selfishness. If I'm pursuing my own self-interest, I might quite rightly choose to cooperate with my peers for mutual benefit.
Conversely, if I don't pursue my own self-interest, what exactly is the point of living at all? It's not like intelligent life serves any objective purpose or end, other than that which we individuals imbue it with.