For starters, this feature does not prevent anyone from expressing their expression. If the administrator removes your “opinion” from a group chat, this does not prevent you from advertising it in p2p chats or a group chat prepared with the same technology.
Moreover, you have to take effective action to be able to talk about censorship at all. Just because the option exists doesn’t mean you’ll use it. Many countries have included self-humiliation in their laws, and few countries actually use this force to enforce censorship.
In addition, sometimes the law requires you to delete certain messages. Just think about distributing personal data or photos without permission.
Anyway, you probably have a very different view of censorship, fortunately we live in Trias politica, so you are always free to challenge this in a court of law. But I think there are very real chances that your case will not be accepted.
Plus, let’s be realistic for a moment, this will mainly be used to remove spam or messages that don’t belong to a particular group conversation. However, if you think they are going to use this to censor your opinion, this says more about your opinion than this feature: https://xkcd.com/1357/
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