Very very few messaging platforms operate without any kind of censorship. Censorship, by itself, is not particularly worrisome, especially when done by first or second parties to the conversation.
The problems arise when the censorship is compelled by third parties who are using it for their own benefit, rather than the benefit of others.
I'd argue that the problems arise whenever the censorship is compelled by third parties, even if they're doing it for the benefit of others.
> Of all tyrannies, a tyranny sincerely exercised for the good of its victims may be the most oppressive. It would be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated; but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience.
The problems arise when the censorship is compelled by third parties who are using it for their own benefit, rather than the benefit of others.