It's not Facebook's nor YouTube's fault per-se but the fault of this bullshit business model based on "engagement". You eliminate that and suddenly there's no incentive for any company to host, let alone use algorithms to promote crap content even if it's nefarious to society.

It’s their business model and their monopoly behavior is designed to crush alternatives.

My point is that you won't solve the problem by merely breaking up/shutting down Facebook or Google - something else will immediately take its place.

If you want to solve the problem you have to eradicate the underlying disease with regulation and then Facebook and Google will fix themselves (by adapting or going out of business).

100% agree

And their system is entirely designed to create echo chambers amongst users. Those groups are easier to manipulate with ads, and naturally there are corps and PACs with motives and money ready to pay to manipulate.