This has zero to do with the 1st amendment. That is between you and the government. You have not such 1st amendment rights when dealing with a private company. All you can do with facebook is either do as they tell you, or drop them. There's not much middle ground.
And at one time, the 1st amendment didn't even exist. Then, the argument was, "You don't even have freedom of speech, so don't bother". Just wait and see, eventually a case will reach the Supreme Court which will make us finally face facts that you can only blur the lines so much when dealing with private companies operating large-scale and general social platforms. After a certain point, it's a public forum and your rights should be equally protected if Facebook is to operate in your jurisdiction.
