This is such a key point. I'd wager that fewer than 1 in 50 Americans have the slightest clue that George Stephanopoulos was a highly placed lieutenant in the Clinton White House. Even without knowing about Steffy's ongoing relationship via the Clinton Foundations, viewers are now going to filter output from this "unbiased journalist" through info they simply didn't have before Trump brought it to light, face to face with Steffy. In two sentences!
Americans take a dim view of deception. You and I know that Stephanopoulos is no more a journalist than whatever actor sits across the "desk" from infomercial fraudster Kevin Trudeau. Now, some of the rest of America knows, too.
Were as many people aware that Bill Moyers was the press secretary for President Lyndon Johnson?