It's bad enough if your emotional response can be influenced by another entity, it's very disturbing if it could be done without you knowing about it.
(I suppose proponents will say 'What you don't know won't hurt you.')
An amusing irony: The technique / technology being used to condition people to have an aversion to Facebook, and the result: -
Current scenario : Most people are comfortable using Facebook, whether or not they're aware of the risks.
Resulting scenario : People are just not comfortable using Facebook --- it's a 'gut' feeling.
