Because the Mainstream Media is the propaganda wing of the National Socialist Democrat Worker's Party, and they take their orders from the DNC - which means never ever report on anything that might help the Trump, the GOP or us Normals who live between I-95 and I-5.
To NBC News' credit, their reporting is the entire reason we know about the discrepancies in Swetnick's accounts. It was their October 1st report—during the height of the Kavanaugh sexual misconduct debate—that first revealed that Swetnick would not or could not confirm several of the details she made in a sworn statement to Congress.
But per the newest story, these are the details NBC News knew for a fact during the Kavanaugh debate, and chose not to report:
I wouldn't read it if you're on blood pressure medication.