The first amendment protects you from (mostly only direct) government retaliation on your speech. It does not define what is and isn't censorship. It doesn't even protect you from the government circumventing it by having most communications go through private avenues and then strong-arming those private entities to regulate speech. And it certainly doesn't protect you from private censorship from massive corporate entities that seemingly want to have a corporate autocracy.

I live in a world where Signal is free, anything can be encrypted, and the major barrier to any of that is human laziness and a lack of interest.

We don't need conspiracies, people stink at this to begin with and most DO NOT CARE. The tech world is a bubble, we are less than 1% of 1%.