How do you tell someone when they are wrong?

Is it better to just let what is so deeply ingrained carry on?

I suppose it's the easiest thing to do.

To let your courage take a rest whilst the underlying problem persists.

Never weakening, never fading, but only gaining more control over it's host.

And all I can do is watch.

A bystander to the destruction caused,
and a victim.

What is the right answer in a situation with no positive outcome?