If nobody ever stole people would not have to lock their doors.
But people steal, so people lock their doors.
If nobody ever lied, people would not have to doubt others’ sincerity.
But people lie, so you do have to doubt other’s sincerity.
If every time somebody said ‘I’m a sick person. I should never have done what I did! I will seek therapy.” they really meant that, then you would not have to doubt the sincerity of such statements.
But people say that as a strategy to blunt criticism and avoid consequences, so you do have doubt the sincerity of such statements.
Fake sincerity gets faker and faker and skepticism must get hyperer and hyperer to react to it in an arm’s race.
Would the world be a better place if people could just trust each other?
I suppose. Better in some ways and worse in others. Certainly less interesting. But maybe less exhausting!