Quoting from Black's Law Dictionary:
"The phrase 'good faith' is used in a variety of contexts, and its meaning varies somewhat with the context. Good faith performance ....excludes a variety of types of conduct characterized as involving "bad faith" because they violate community standards of decency, fairness or reasonableness..."
Good faith is a basic requirement for civil discourse. Without it there is no point in discussing anything. If your opponent in a debate is constantly lying about his position, or having changed his position fails to note that change and/or claims he has not changed positions at all it is impossible to reach any meaningful conclusion, other than that your opponent is acting in bad faith.
At the link http://pjmedia.com/eddriscoll/2015/05/04/nbc-geller-caused-texas-shooting/
is an excellent example of how and why liberals operate in bad faith. Always.
In a three month period of time Matthews' opinion changes 180 degrees. The only apparent reason for the change is that the actor being described has changed from a left wing publication to a right wing activist.
Matthews does not bother to tell us; 1) What his original opinion was; 2) Why he changed his mind; nor 3) Which of his two diametrically opposed positions is his real opinion.
This is standard procedure on the left. See my earlier post regarding the 2013 SOTUS.
One of my favorite examples of this tactic is courtesy of the NY Times. When republicans controlled the Senate in the mid-1990's NYT editorialized that the Senate filibuster rules were the cornerstone of American political freedom. 10 years later, with republicans now in the minority and making things difficult for the democrat majority the NYT editorialized that the filibuster was an anti-democratic construct that threatened the very cornerstones of American political freedom. No reference made to the earlier editorial on exactly the same subject and no explanation for their change of heart. Bad faith actors all. (http://www.washingtonexaminer.com/then-and-now-the-hilarious-hypocrisy-of-new-york-times-editorials-on-the-filibuster/article/2539617 is a story about a third incarnation of their thinking based on their 2005 position and their 2013 position)
It must be so when your only principle is the quest for power and your determination to make sure your opponents are kept from it.
Chris Matthews was a speech writer for Jimmy Carter during the latter's Presidency.