True. However, they were trying to escape death themselves.
The prosecutors would allow a confession with evidence of repentance as reason for allowing the person to be released. Refusal to confess was taken as evidence of guilt.
Evidence of repentance essentially required accusation of others.
Making such accusations was a wicked thing to do, but a very human failing when in fear of death. The primarily responsible parties are those who put the "witches" in this position.
We should also remember the heroic Giles Corey, who not only refused to accuse others, but refused to plead guilty or not guilty. He was therefore "pressed" to death, crushed under a pile of stones. This meant his family inherited his property, which would have been confiscated if he was convicted.
http://en.wikipedia.org/wiki/Giles_Corey
In a truly classic example of "F U," his last words were "more rocks."
The Crucible was a work of fiction/propaganda. The false accusations by those already charged (and guilty of being witches in the book) were supposed to make Americans skeptical of those named by known Communists.