You have got to be kidding. I don't think I've ever seen anyone defend MacArthur's approach to the Yalu. So congratulations, I guess.
First, MacArthur wasn't racing to the Yalu to beat the Chinese. He didn't believe the Chinese were going to cross the Yalu period. He and his staff repeatedly rejected/minimized all reports of contact with Chinese forces that contradicted this belief. He completely bought into the Chinese propaganda of it being just a few "volunteers" who crossed on their own initiative. And he personally assured Truman that the Chinese wouldn't intervene on the ground, and if they did, he would crush them. He was horribly wrong.
The only reason for the rush up to the Yalu was so that MacArthur could claim "home by Christmas", which would be a nice feather in the cap of his career. There was no military justification for it at all, nor did he advance any.
But if had believed that the Chinese were going to intervene, ordering the VIII Army and X Corps to race north, with a sixty mile gap in lines creating a gigantic flank along the Taebek Plateau, would have been criminal stupidity. As it turns out, VIII Army was blasted, a U.S. Army division broke, some allied contingents were completely wiped out, and the First Marine Division barely escaped annihilation. And again, only due to General Smith and his staff delaying movement for a couple of days to consolidate before pushing north.
Whatever his other merits as a general, and they are very considerable, the advance to the Yalu was a complete catastrophe for which he deserved full blame.
After Inchon where were intelligence failures. The only thing I can say in his defense is that everyones' intelligence failed too. No one thought or even guessed that the Chicoms had moved into Korea in mass. But the fault rightly falls on the commanding general so yeah, he takes the hit for the bad intelligence. But I place the blame on Truman's patrolling the Taiwan straights which freed those chicom troops for duty in Korea.