People have been mentioning some of his narcissistic traits since the loss. If they're right and he's a major narcissist (and I can believe that), then moves like this make perfect sense. It's not really intelligence, it's that narcissists feel an absolute need to prove they're right and the rest of the world is wrong. Since the Matthews-Marner pairing wasn't part of the Babcock plan and the press kept asking about it, Babcock NEEDED to prove it wouldn't work and thus he was right to disregard it.
Narcissists like to win, but if they suffer narcissistic injury (like having their decisions questioned), it's easy for them to forget about the win in favor of proving they know everything. I deal with my father every day; he's a great example. He so badly needs to be right in every argument that he'll flip opinions, even during conversations, to make sure his opinions are correct. If you manage to win an actual argument against him, he gets angry and shuts down the entire conversation, by yelling or using one of his patented "end the conversation" techniques ("You're being too loud!", "No, you have to be right. I'm done arguing.", "Whatever you say.", etc.). If you make mistakes, he'll drag them out months or even years later to criticize you, but when he makes a mistake he gets mad if anyone points it out or says anything. He has to be 100% right and 100% perfect all the time.