Creating an artificial system such as the ones which are today mainstream can have undesirable side-effects.
What stops a group of indivudals (or bots for that matter) from injecting rule-breaking content into an otherwise-acceptable thread?
Soft-censorship and derailing is done on purpose to censor certain topics which go against the establishment status quo. Reddit is fertile with such examples. If someone is making a comment which does not bode well to those in power, it is common for the thread to be sunken with low-class behavior and baits in order to shut down valid discussion by forcing an emergence of rule-breaking content.
That is a far more greater threat.
How do you propose to mitigate that?
Moderation is keeping people on topic of the forum, killing spam, trolls and sockpuppets, removing abuse and so forth, and trying to keep things on the rails and civil. Including banning trouble makers. Rather like dang does around here. That's not censorship, it's attempting to avoid anarchy. Neither is limiting the range of topics the forum or platform wants. Standards and extent will vary depending on the aims of the site.
Censorship is suppressing a view, even if it follows the standards and allowed topics of the forum. Legal censorship is a little more complex as standards vary between countries.
Having a post removed because it's spam, abusive or is off-topic is not censorship, which was the point the GP was erroneously trying to make.