Not so much rationalize - he's actually putting it on a statistical and quantitative foundation. There's a fundamental difference between arguing from narrative and history, and technical arguments based on the statistics of how people actually vote based on polling.

Worse that that, he's demonstrating that the 'access' and 'insights' and 'instincts' on which their status as Notable Pundits depends is actually worthless. They are simply making shit up, and what they invent is invariably a tight race scenario because that's what gets the most profitable ratings. In othr words, he is demonstrating both their fraudulence and the disservice they do to democracy. And people LOVE him.

"... what they invent is invariably a tight race scenario because that's what gets the most profitable ratings."

I disagree. I much prefer the article's explanation for why they invariably invent a tight race: journalistic 'objectivity'. As Coddington pointed out, when all the highest sources on both sides of the campaign say it's tight, who is Silver to disagree?