Certainly social bonding serves a Darwinian purpose in terms of protection, resource sharing, infant rearing.
There are lots of pack animals in the world, but as far as we know there has never been a species capable of abstract thought the way humans do.
Their are also unique Human behaviors that have nothing to do with bonding: the wandering ascetic mystic in India, the solitary Christian monk in the Egyptian desert, the Greek natural philosopher contemplating the cosmos.
As far as we know, we are the only species that contemplates the meaning of life, creates art, creates religion, performs abstract reasoning.
Altruism in the mammalian world seems to only function in family groups or packs. That makes evolutionary sense. I've never heard of a lion pride bringing food to a different lion pride.
I really don't think we can point to Charles Darwin to explain it all. I am prepared to admit that science, as it currently stands, does not explain everything about everything. There may be a science of mind or a science of conciousness we haven't even invented yet that will provide better insights into the human behavior