> But that would be called realism, not nihilism.
What a nihilist calls realism is nihilism - what an optimist calls realism is optimism - etc.
Show me someone who doesn't say "I'm a realist" and i'll show you a confused person.

What you've written implies that humans are incapable of getting together and accomplishing anything of value as a group.
I don't see it that way.
When Eve bit that apple, she planted foibles in each of us, but nevertheless I see people - in public and private jobs - doing wonderful things every day.
They don't make good copy for journalists -while mass shootings or big government screw ups do- so we tend to focus on the foibles.
I recently stumbled across "Halt and Catch Fire" on Netflix and it reminded of me of some of the amazing (and quite weird at times) people I've been fortunate to meet in our profession.
We've accomplished a lot as a group and you and I wouldn't be exchanging these ideas on the internet unless some people somewhere somehow figured out a way to cooperate with each other.