No he didn't.
He continued to lie to the grand jury by perpetuating the narrative that Wilson was the aggressor who shot Brown in the back.
And DID matter when he told bald face lies to the media.
Where do you think the " hands up dont shoot " BS came from ?
His lies to the media incited riots and violence.
Why would Wilson feel that his life wasn't in danger after Brown had already gone for his weapon ?
After Brown had already assaulted him ?
And yes, Lawrence O'Donnell is a unmitigated hack and he's not too intelligent to boot.
He bought into all of the lies and false narratives that whipped this whole issue into a frenzy in the first place.
“I think if Thomas Jefferson were looking down, the author of the Bill of Rights, on what’s being proposed here, he’d agree with it. He would agree that the First Amendment cannot be absolute.” - Chuck Schumer (D). Yet, Madison and Mason wrote the Bill of Rights, according to Sheila Jackson Lee, 400 years ago. Yup, it's a fact.
"The law is reason, free from passion."