How can we reconcile the "Salem Witch Trails" with the idea that the Christianity brought by these settlers...

You cannot reconcile the SWT's...they simply demonstrate that any uncontrolled power base will do anything to expand its absolute power and even religion will also avail its social power and status to destroy dissidence in any and all forms along with the removal of the socially disadvantaged if the majority loses its social compion....unless of course a secular power base is available to balance the "other power(s)....(PS this also works the opposite direction)...