I agree with you but this is an incredibly hard problem to solve. How are you going to get your friend to engage with videos that are in direct opposition to her world views? Recommendations are based on what she actually clicks on, how long she actually watches the videos, etc.
And from the business perspective, they're trying to reduce the likelihood that your friend abandons their platform and goes to another one that she feels is more "built for her".
A start would be to recognize that businesses are not allowed to exploit this aspect of human nature because the harm is too great to justify business opportunity.
It's easy to solve. FB gets to either be a platform for content or a curator for content. They can't be both because that would be a conflict of interest.
Then what's the business model? Who pays for all of it?
I'm not defending a specific approach or solution, but just pointing out that at this point, FB is a huge entrenched business that makes a lot of money on the status quo, and so convincing them to change "for the better" is barking up the wrong tree until "for the better" means "more profitable".
Splitting the platform and curation means the platform needs a revenue stream. If the curator pays the platform, then all you're doing is shifting the conflict up a notch, not solving it.
And from the business perspective, they're trying to reduce the likelihood that your friend abandons their platform and goes to another one that she feels is more "built for her".