I'm currently reading about MacArthur's reconquest of the Phillipines. MacArthur went to great lengths not to punish those who collaborated with the Japanese puppet government, the Laurel regime, in Manila. (Partially, it is said, because he had social friends who were compromised, and anti-collaborationist fervor would have ended their public lives.) The fact that MacArthur fought to clear the names of his friends enervated the court set up to try collaborators, essentially taking away the credibility of the only truth and reconciliation the Filipinos would get.
One of those MacArthur fought for was Manuel Roxas y Acuna, who quickly rose to power through the senate and into the presidency. His regime established the pattern of corruption and violence that would characterize the government, culminating in the Marcos regime.
Meanwhile, of course, the Huk rebellion intensified. The Hukbalahap began as a resistance movement against the Japanese occupation -- kind of the the Free French of the Islands. After the war, they saw the pardoning of upper- and middle-class Laurel collaborationists as an insult, and were forced to watch these bureaucrats reassume control of the country they had betrayed, and that the Huk had fought for. One can fault the Huk rebellion for turning to the communists for aid and ideology, but one can hardly be surprised that they did. (Imagine if the first president of liberated France had been a high Vichy official, then put yourself in Chas. De Gaulle's shoes. You might have picked your gun and started calling your old resistance buddies.)
All this is nothing definitive, simply counterexample. But I wouldn't be too quick to fault the CPA for their purge.