Some people react quite viscerally to the awareness that another party is trying intentionally to steer their behavior in any way. It seems to just be a massive squick button for some (indeed, I notice that most randomly-selected people who are made aware of explicit attempts to condition behavior react with discomfort at minimum); for others, there seems to be a correlation with triggers gained from abusive interactions earlier in life; a few I knew who reacted strongly showed strong indications of sociopathy and seemed to instinctively feel violated if someone else successfully, or even just obviously, tried to affect their behavior in a deliberate manner toward some end (a normal part of cognition and social interaction for them directed at others).