To the degree that Facebook is the private property of its shareholders, it's correct to say that they have violated no rights of Alex Jones and that, if anything, he has violated theirs.

If I invite you into my house and you begin to spew nonsense and I kick you out, I have not censored you, I have not violated the First Amendment, and I have not violated your rights. You have violated mine by not respecting my wishes on my property.

That is not to say that the decisions were moral, ethical or even good ones. It is simply how private property and freedom of association work.