I never said they got revenue from a link. They make their revenue by showing you ads, and they use various strategies to make you stay longer on their website so they can show you more ads. One of these strategies is to include news articles in your feed, either shared by your friends, shared by the news organizations themselves (in a desperate bid to get you to visit their website), or just as suggested stuff.

They captured a huge chunk of the advertising market, and it's happening at the expense of other businesses who provide a useful service to the people. I won't pretend that they aren't useful themselves, but I think they reached a point where they've stopped seeing that as a goal, and are instead focused on antisocial objectives (showing you more ads).