Giddonah does not pass judgment, but sends Korihor to Alma, the chief priest, as well as to the chief judge (this is clarified in verse 51). Korihor is not simply a man who might be guilty of lying, but a man who was subversive to the entire Nephite way of life.
When Korihor comes before Alma, he continues the same arguments that he had used in Gideon. There are two aspects to Korihor’s accusations against the Nephite religion. The first is that they do not teach truth, but rather “the silly traditions of their fathers.” This repeats the argument that it is the scriptures that lie, not Korihor. The second accusation is that the reason for Nephite religion is so that the priests can “[glut themselves] on the labors of the people.”
Since Korihor is a man who came into the land of Zarahemla (see Alma 30:6), it is possible that he was from some non-Nephite land and was not aware of the fact that it was an important Nephite teaching that the priests labor with their own hands for their support. Alma will make certain to bring that up as part of the revelation of Korihor’s lies.