Because language is necessarily often ambiguous.
The ambiguities are rarely fixed.
Unfixed ambiguities lead to errors in interpretation. The errors accumulate and snowball. All people have been raised in environments like that and continue to live in them.
This causes pain because our minds are capable of communicating unambiguously, but we don’t know how.
We are semiotic animals, beings that live in semiotic jungles.
Our pain and error-ridden communication makes us mean, simple, greedy, stupid, violent, selfish, crazy.
Communication errors, misinterpretations, cause ghosts to form in the mind. We need to imagine a role for ourselves and others, but since we experience so many errors, our imaginings are fundamentally wrong. They are like ghosts in our minds.
We are as ghosts speaking and listening to each other.