I think your point has its limitations but is quite important. "Just turn off FB" sounds similar to "Just build your own social media", it may be seen as too limiting.
On the other hand I think people against non-censored speech often frame the receivers of the message as somehow mindless. Now that I think about it, censoring people on social media (i.e. deplatforming Trump) implies that users have no free will (whatever that means) and can only act as an obedient crowd. From that perspective, everyone who might become a leader of the masses seems dangerous and requires intervention. Not only that, their followers are also potentially dangerous, just not powerful enough. To me such attitude is in contradiction with individual's freedom to express their views but also a denial of existence of freedom to act in accordance with one's views.
On the other hand I think people against non-censored speech often frame the receivers of the message as somehow mindless. Now that I think about it, censoring people on social media (i.e. deplatforming Trump) implies that users have no free will (whatever that means) and can only act as an obedient crowd. From that perspective, everyone who might become a leader of the masses seems dangerous and requires intervention. Not only that, their followers are also potentially dangerous, just not powerful enough. To me such attitude is in contradiction with individual's freedom to express their views but also a denial of existence of freedom to act in accordance with one's views.