It could be argued that private companies censoring you violates your first amendment rights. And it probably will be decided by the supreme court in the next few years.
Free speech is a concept, not just the bare letter of the text of the bill of rights. [1]
And there are examples of private companies being forbidden from censoring or removing people.
For example, the courts ruled that a private airport was forbidden from kicking out people who were there to hand out flyers. [2]
And, do you seriously think it is ok for the private electricity company or the postal service to deny access to their network because they disagree with your politics? Is it really ok, just because "property rights"?
The first telegram network was a total monopoly, and was used as a tool by the wealthy to manipulate elections and tamper with commodities prices.
It was because of this that we got common carriage laws.
Back then, would you have defended the telegraph company banning journalists who criticized labor practices in coal mines? Why not? It's their private property after all. Those labor organizers and human rights activists should have thought about the consequences of their actions before attempting to expose child labor.
[1]: http://magaimg.net/img/5yri.png
[2]: https://blogs.wsj.com/law/2007/12/26/ca-supremes-give-free-s...