Sometimes I feel that the free market argument doesn't apply to media platforms. This is because the effectiveness of a media platform (or any mass media, for that matter) is largely determined by its market/usage share; in other words, smaller or alternative media platforms cannot be considered as a working substitution to the dominate platforms. And since the user distribution of social media tends to follow the power law (i.e. the "can't switch 'cause all my friends are using it and they won't switch due to the same reason" phenomenon), it is almost inevitable that a single platform will eventually monopolise the sector if left unregulated. banning a user from using the most popular media channel would mean he/she is no longer able to communicate his/her opinion effectively even he/her is able to choose a less popular alternative.

tl;dr: one can always switch their phone if they don't like Apple because the usefulness of a phone doesn't depend on its popularity; one can't practically switch their social media platform if they are banned because the usefulness of the social media depends on its popularity, and the most popular platform typically dominates due to the power law.