But you’re ignoring their own freedom of speech. If party A wants to voice something through party B, and party B does not want to express it, their freedoms of speech are in conflict. You cannot resolve this without one party not being allowed their freedom of speech.
And if the answer is it’s always in party B’s court, then you make the situation very difficult when it comes to social media and even direct messaging platforms between two private entities.
I have specifically said that they have no obligations. But if they silence an opinion because they don't like it they don't adhere to the principle of freedom of speech.
I don't think social media platforms have any legal obligation to allow anyone to state anything. It was a culture that had formed on the net in most places. I has no relation to the law or the US first amendment in any way. It was a foundational rule for the exchange of ideas and that always requires freedom of speech.
Also, almost every institution that want intellectual exchange has to adhere to the principle because it is a fundamental part of dialectic. Many educational institutions are falling short here lately, but at least most are improving again. But that is a completely different topic.
People that silence others without a justification are rightfully looked down upon in my personal opinion because they are not capable of intellectual exchange. And these ideas are also enshrined in human rights for a reason, although these are sadly also not really legally binding.
And if the answer is it’s always in party B’s court, then you make the situation very difficult when it comes to social media and even direct messaging platforms between two private entities.