Marsh v. Alabama, 326 U.S. 501 (1946), was a case decided by the United States Supreme Court, in which it ruled that a state trespassing statute could not be used to prevent the distribution of religious materials on a town’s sidewalk, even though the sidewalk was part of a privately owned company town. The Court based its ruling on the provisions of the First Amendment and Fourteenth Amendment.
https://en.m.wikipedia.org/wiki/Marsh_v._Alabama
I am missing your point. Facebook is not a public government owned space. Further, Facebook is not the government. So, a private company controlling access to private property is far away from the government controlling speech, the very definition of un- Constitutional censorship, on government property.
Facebook should remain free to blacklist as much as it wishes.
The cake baker case was exactly about this matter. Private people should not be forced to express someone else’s speech.