Why we need a right not to be manipulated

Came across an interview with Cass Sunstein by Tyler Cowen, which covered many things, but where this idea of a right to be free of manipulation came up. I found this article Sunstein wrote about the topic a few months ago. Apparently part of a promotion tour for his book https://www.cambridge.org/core/books/abs/manipulation/right-not-to-be-manipulated/FBB35C24137F78950566867F1D348AB0