If the surveys are created as ungraded surveys, Canvas does not allow resetting the points to zero.

As a workaround, you may need to: 

  1. Create the survey as a graded quiz, add in your questions and edit the point value for each question to zero point. 
  2. Once the survey questions have been added, and points adjusted as required, change the quiz type from 'graded quiz' back to an 'ungraded survey'.

The questions in your ungraded survey will now be reflected as 0 points.