Welcome to Thedas. Everyone is afraid of everyone for their own reasons, some valid, some not. I cannot offer recommendations on how to change the public's opinion on rifters- if I knew the trick to that there would not be quite so much fear and distrust surrounding mages.

All I can say is do what we do. Work for the betterment of the Inquisition, assist where and how you can, if you can. Actions, after all, speak louder than words by far.