If you will not do it for you,
do it for the next person.
Put them on Notice
There are times when a person's behavior is unacceptable to us and
they refuse to take responsibility but we are not ready to isolate them.
In this instance we should emphatically communicate what we think.
Let them know that they have let us down.
Perhaps even tell them that if it happens again, severance is possible.
Sometimes it is enough for people to receive a warning to effect change even when they fail to acknowledge their error.
In the end, though, if we do not tell them at all, we become enablers.
Perhaps they will hear the same from an independent source and decide that it is time to take personal responsibility.
Regardless, it is up to us to let them know how we feel.