This is like saying a Tesla car is just a machine that generates heat.
Facebook has built an algorithmically optimized list of content that they believe will drive you back to the site to consume more.
They also have insane amounts of usage data which they are testing for sentiment analysis [0] They've also run tests on content to provoke emotion as far back as 2014.[1]
It's clear that they have the power to influence emotions and impact people in real ways. Because you are strong willed does not mean that others cannot be easily swayed by dopamine release.
[0](http://money.cnn.com/2017/11/27/technology/facebook-ai-suici...) [1](https://www.theatlantic.com/technology/archive/2014/06/every...)