Today's social media landscape is extremely centralized. The vast majority of users are concentrated on only a handful of platforms like Facebook, Reddit or Twitter. All of these are maintained by large corporations that are subject to profit motive and United States law. In recent years these platforms have increasingly censored users and entire communities, often with questionable justifications. It is only natural that those who are affected by this search for alternatives. This document is intended to help with the evaluation.
For this purpose we will consider as censorship anything that prevents a person from expressing their opinion, regardless of any moral considerations. All the options explained here also have legitimate uses, such as deleting spam. Nevertheless it is important for users to understand why their posts are getting removed and how to avoid it.
The first and most common source of censorship in this sense is the admin of a given Lemmy instance. Due to the way federation works, an admin has complete control over their instance, and can arbitrarily delete content or ban users. The moderation log helps to provide transparency into such actions.
The second source of censorship is through legal means. This often happens for copyright violation, but can also be used for other cases. What usually happens in this case is that the instance admin receives a takedown notice from the hosting provider or domain registrar. If the targeted content is not removed within a few days, the site gets taken down. The only way to avoid this is to choose the hosting company and country carefully, and avoid those which might consider the content as illegal.
Another way to censor is through social pressure on admins. This can range from spamming reports for unwanted content, to public posts from influential community members demanding to take certain content down. Such pressure can keep mounting for days or weeks, making it seem like everyone supports these demands. But in fact it is often nothing more than a vocal minority. It is the task of admins to gauge the true opinion of their community. Community members should also push back if a minority tries to impose its views on everyone else.
All of this shows that it is relatively easy to censor a single Lemmy instance. Even a group of instances can be censored if they share the same admin team, hosting infrastructure or country. Here it is important that an admin can only censor content on their own instance, or communities which are hosted on his instance. Other instances will be unaffected. So if there is a problem with censorship, it can always be solved by using a different Lemmy instance, or creating a new one.
But what if the goal was to censor the entire Lemmy network? This is inherently difficult because there is no single entity which has control over all instances. The closest thing to such an entity are the developers, because they can make changes to the code that all the instances run. For example, developers could decide to implement a hardcoded block for certain domains, so that they can't federate anymore. However, changes need to be released and then installed by instance admins. Those who are affected would have no reason to upgrade. And because the code is open source, they could publish a forked software version without these blocks. So the effect would be very limited, but it would split the project and result in loss of reputation for the developers. This is probably the reason why it has never happened on any Fediverse platform.
Lastly it might be possible to abuse software vulnerabilities for network-wide censorship. Imagine a bug in Lemmy or in the underlying software stack which allows the attacker to delete arbitrary content. This could remain undetected for a while if used sparingly, but would certainly be discovered after some time. And experience has shown that such critical flaws are fixed very quickly in open source software. It is also highly unlikely that critical vulnerabilities be present in multiple different Fediverse platforms at the same time.
In conclusion, the best way to avoid censorship on Lemmy is through the existence of many independent instances. These should have different admins, different hosting providers and be located in different countries. Additionally users should follow the development process to watch for changes that might create a centralized point of control for all instances. Based on this explanation it should be clear that censorship on Lemmy is difficult, and can always be circumvented. This is in contrast to centralized platforms like Facebook or Reddit. They are not open source and can't be self-hosted, so it is necessary to switch to an entirely different platform to avoid censorship. And due to lack of federation, such a switch means losing contact with users who decide to stay on the censored platform.