My point was that people will always be people. We all screw up and tend to follow the herd most of the time.

You completely glossed over the fact that such social media experiments show that it is indeed possible to target and manipulate particular demographics based on their social media/ net habits.

For example, Someone with access to all the google, twitter and facebook meta-data and the motivation and resources to mine it can easily divide people in groups as being favorable/ non-favorable to a particular candidate or proposal. They can then target the users accordingly to shape their opinion.
Denying that its always only "stupid" people who fall for such tactics is giving too much credit to your own thought process. A majority of people will change their opinion when bombarded with a particular ideology on their social feeds for a long enough time.