I have to say that I have seen this type of censorship with my own eyes in two ways:
1 - What I have noticed in FB lately is that any posts that appear on my feed that are criticisms of Biden or anything on the left, will have a fact check section right below the post linking to a website that attempts to discredit that criticism. Now, this perhaps this would seem like a good idea, until you realize this is only done in favor of Biden and it's done across the board on every criticism. So basically if you were to believe FB, every single criticism of Biden is false, and deserves fact checking, and every single criticism of Trump is true. I have yet to see one criticism of Trump that is complemented with some fact checking.
2 - Facebook actively censors even posts. I replied to a post recently about the protests where I made the point that BLM and much of the protests are centered around Marxist ideology. I received several replies to my comment where we exchanged some comments and where I supported my comment with facts and data. In less than 5 minutes after my initial post, my comment and all the replies were gone and unavailable to comment anymore. They magically disappeared, which I was baffled that it was removed so quickly. Of course all other comments in the main thread were still there, but mine was gone.