> I don't see how this is true unless you're just talking about Facebook's non-chronological order.
It's more than just non-chronological. FB buries many link posts. Specific friends can disappear from your feed for months. FB still has the echo chamber issues it had pre 2016 election, just with fact checking notations sometimes. For many people, FB is where they get their world news at this point, and that's a very skewed way to get your news.
You get posts from people/pages you subscribe to in your feeds. I don't see how this is true unless you're just talking about Facebook's non-chronological order. Twitter's nothing like that anyway.