Why is it that the majority of people 'SEEM' to believe that ‘human nature is inherently “evil”’

I think it is because not enough people believe in standing for whats good anymore. Everyone just wants to let someone else clean up the mess so that all we're left with is a darkness with almost no light of hope. I say almost none because i hope the there are still those who can still see a glimmer of hope for the good of humanity as i still do. If there isn't then whats the use of trying to save this world?