Hale, a round character, undergoes a change. As the trial progresses, he becomes increasingly skeptical about the accusations and evidence of witchcraft. He also becomes increasingly skeptical about the culture of Salem as he begins to see how they unite via accusations rather than being united in a more Christian spirit of fairness and generosity. He also begins to seriously question the governing bodies, including Judge Hathorne. Hale was originally sent to investigate the accusations of witchcraft and therefore his goal was to uncover that very thing. In the end, he uncovers the lies behind the accusations as well as the corrupt practices of the town's leaders.
When Hale begins to believe John and thinks that Abigail has been lying, this goes against the court's biased opinion. Danforth is a completely flat character; he will simply not change his mind. His attitude is that anyone who goes against the court is lying. Hathorne is not as stubborn but is similarly biased by the court's final decisions. When Hale returns from Andover to plead with Hathorne and Danforth to consider that all accusations have been lies, Hathorne refuses to believe it:
It is no lie, you cannot speak of lies.
It is very clear that Danforth will not have the court challenged, even by Hale. Hathorne also doesn't want to think that the court was wrong. Miller, in a side note, describes Hathorne as a "bitter, remorseless Salem judge." If this attitude holds true to the end, then he would dismiss Hale's change of heart as pointless or useless. In this case, whereas Hathorne initially viewed Hale as an ally, he now sees Hale as an enemy.