Question

explain why proctors knowledge that the children's sickness had naught to do with witchcraft” did not stop the witch hunt and court proceedings

Answer 1

Proctor is most likely not taken very seriously because the people of Salem were very quick to jump to conclusions based on one's reputation.
Proctor was not liked by the majority of the community. He was very intimidating. People were suspicious of him because he did not go to church on Sundays and he worked on Sundays as well.

Answer 2

In "The Crucible" by Arthur Miller, the witch trials in Salem, Massachusetts are unstoppable and the entire community is involved. John Proctor, a local man who is not seen as devout as he does not go to church every week and does not have a great reputation is one of the few to speak out against the finger-pointing. Saying that you didn't believe the children were afflicted by witchcraft only made you a suspect, especially if you didn't have a good reputation in the church-going community.