They already have though. My friends seem to draw political posts in their feeds from two different pools, depending on the user's affiliation.
[0] https://newsroom.fb.com/news/2017/01/continuing-our-updates-... [1] https://gizmodo.com/former-facebook-workers-we-routinely-sup...
This is important for community admins to understand. This is not a dialogue problem. People are given a tribe to belong to or oppose, and these affiliations are used by strategists and propagandists to affect popular anger/resentment.
That means that users don't want to see a balanced feed. They want to see things that make them feel good things, and not bad things. And the other side is "bad things".