It's not just your circle that determines what show up in your feed. The algorithms re-enforce peoples views by putting stories in your feed it thinks you will

It's not just your circle that determines what show up in your feed. The algorithms re-enforce peoples views by putting stories in your feed it thinks you will 'like'. If it thinks you're pro-Trump, you will have more pro-Trump stories even if you have an even mix of Trump/Hillary supporters in your circle. Many times the sensational stories that are most likely to be 'liked' are also the fake ones. There no warning that the story came from an unreliable source.