Eh, people have lots of friends that hold different beliefs than them. The problem with Facebook is it offers no way of registering your disagreement beyond commenting and starting a conversation which will have no depth because the lack of real comment threading renders any real dialogue impossible.
Since most people don't feel like repeatedly getting involved in pointless debates with their friends, and are frustrated seeing posts they disagree with without any simple way of voicing their disapproval, they either use Facebook's tools to filter out those posts or just unfollow that friend entirely.
The most misguided consumer and propagator of fake news will still mostly just see likes of their friends who are also misguided. They might get a brave friend chiming in here or there to disagree, but their comments are easily dismissed because they will have no depth. The majority of their friends may disagree, but they'll never know because those who disagree (if they haven't filtered/unfollowed them already) have no good way to show that they disagree. Facebook as it is currently designed mostly just serves to affirm whatever the user wants to believe. That's where the bubble effect comes from.
You can avoid a conversation and post in opposition. You can suggest dissent by "like-ing" with a sad or angry face.
If you make a post with an opposing view, or share someone else's then your friend group can use that opposing post to show their dissent for the initial post.
Since most people don't feel like repeatedly getting involved in pointless debates with their friends, and are frustrated seeing posts they disagree with without any simple way of voicing their disapproval, they either use Facebook's tools to filter out those posts or just unfollow that friend entirely.
The most misguided consumer and propagator of fake news will still mostly just see likes of their friends who are also misguided. They might get a brave friend chiming in here or there to disagree, but their comments are easily dismissed because they will have no depth. The majority of their friends may disagree, but they'll never know because those who disagree (if they haven't filtered/unfollowed them already) have no good way to show that they disagree. Facebook as it is currently designed mostly just serves to affirm whatever the user wants to believe. That's where the bubble effect comes from.