How was Reverand Hale responsible for the witch trials?

In Act One, when Reverend Hale comes to town, he is very willing to believe that witchcraft is at the root of the town's problems, and so he fails to recognize the likelihood that Tituba would lie to escape hanging. When she claims that she isn't in league with the Devil, Reverend Parris, her owner, shouts, "You will confess yourself or I will take you out and whip you to your death, Tituba!" and Putnam...

In Act One, when Reverend Hale comes to town, he is very willing to believe that witchcraft is at the root of the town's problems, and so he fails to recognize the likelihood that Tituba would lie to escape hanging. When she claims that she isn't in league with the Devil, Reverend Parris, her owner, shouts, "You will confess yourself or I will take you out and whip you to your death, Tituba!" and Putnam yells, "This woman must be hanged! She must be taken and hanged!" Not coincidentally, it is at this moment that Tituba begins her confession. If Hale had not been so willing to see witchcraft at the root of Salem's troubles, he would likely have realized that Tituba was only confessing out of her extreme fear of punishment.

In Act Two, early on in the court's proceedings, when Rebecca Nurse is charged with witchcraft, Hale says,

Believe me, Mr. Nurse, if Rebecca Nurse be tainted, then nothing's left to stop the whole green world from burning.  Let you rest upon the justice of the court; the court will send her home, I know it.

He knows that Rebecca is innocent, and yet when the court finds her guilty, Hale does nothing. In fact, he signs her death warrant himself. Had he protested or objected more forcefully early on, it might have had some effect on the court before the trials got even more out of hand.

Later, in Act Three, Hale says how uncomfortable he is with the fact that he has "signed seventy-two death warrants," including the warrant for Rebecca Nurse (despite his earlier statement that there was no way she could ever be found guilty by an honest court). His conscience is clearly weighing on him, as he admits that, since signing her warrant, "[his] hand shakes [...] as with a wound!" After Mary Warren's deposition, when she turns on John Proctor, Hale believes that "this child's gone wild!" though Danforth will not listen.  By the end of the act, Hale gives up, saying, "I denounce these proceedings, I quit this court." And he leaves. Hale realizes that this court is corrupt, and rather than stay and fight to protect the innocent victims, he runs away. This is a shameful way for him to behave, especially as a member of the clergy. Had Hale been more adamant in his objections to the court, had he refused to condone the proceedings, or had he simply refused to leave when things became difficult, he might have been able to stop the deaths of many guiltless people. Instead, his lack of action allowed the trials to move forward.