Don my understanding of the engineered goal of social media sites is that it isn't intended to cause pleasure but to create addiction. Which has been called wanting without liking. They are pretty good at creating that response.
But doesn't Epicurus tell us that there can be only two reactions: pleasure or pain?
Sometimes people can feel pleasure at having biases confirmed, but much of the politically biased content is angry/paranoid in tone. It's possible for people to get hooked on the excitement of anger with really getting much pleasure from it.
But can't people take pleasure in their anger? Self-righteous anger elicits pleasure not pain ("The feelings are two.").
And the addict experiences pleasure from the hit but pain when it's not present.
. I read a book on artificial flavoring, the Dorito Effect
That was a fascinating book. Read it a couple years ago.