Almost everybody believes a sizable part of the population to be brainwashed, they disagree on what part it is however.
And I do very much believe that it is a discussion worth having for society at large. Do we believe that we are generally aware of the dangers of things we do? Is outlawing oversized sodas the right thing to do? Would it be okay to allow them only if you can use a code word that signals that you do, in fact, understand the risk? Do we not like that approach at all, or do we just not want to deal with deciding who understands the risk and is able to walk down the stairs and who isn't?