I can definitely see what you are saying. Listen, I'm no huge fan of Brian Williams. I think he's a colossal douche. Maybe I'm more bothered by why some other journalist would go out of their way just to track down a stupid lie.
Except, that is not what happened.
What happened was, the veterans who WERE on the chopper that got shot down, tried to tell NBC Brian was lying. And had for years. They never listened, and the vets couldn't get anyone else to listen either - until the blogger you mentioned earlier, broke the story and social media took off with it, forcing Lyin' Brian's subsequent acknowledgement of his lie, and apology to the vets.
THEN the WaPo and others investigated, and found the other dozen or so outright LIES this guy has told over the years. Such as, seeing a body floating down Bourbon Street from his hotel window during Katrina, and etc. Bourbon Street never flooded to anywhere near that degree, he just made it up out of shit he pulled out of his ass.
Finally someone listened to the Iraq chopper vets.