People like to hear this phrase “it is not your fault”.
The tendency of human being is to assert that he or she is right most of the time. When challenged, they would defend themselves.
So it will come as a great pacifier if you were to use the phrase when making a speech or selling something. They would feel closer to you since they find that you understand them and stand side by side with them.
When you are on the same side as them, chances are they trust you more. A rapport could thus be easily build up.