Depends on why you're complaining about censorship. If you're talking about some God-given right to free expression, sure, complaining about censorship is ridiculous. But if you're talking about what's best for a community, complaining about censorship is a good way to motivate change. People start asking, "Why, exactly, are we censoring these viewpoints? Is it for a good reason, e.g. preventing trolls from taking over discourse, or is it for a stupid or even malicious reason?" Stuff like that is what gets rid of toxic leadership. On the Internet, it usually manifests itself in all of the high-quality folks going elsewhere.
Basically, relatively few people have a problem with the idea of censorship; a certain amount of moderation is necessary on an Internet forum to prevent shitposting. What people are decrying is misguided, stupid, and / or malicious censorship - either due to juvenile power games on the part of the moderators, or due to an external agenda that said moderators are pushing.
Why are "rights" and "complaining" related? It is generally the case that my rights include both things I should do and things I should not do, and it is generally the case that a healthy, free society encourages people to figure out what they should do via discussion ("complaining"), instead of via suppression of rights.
For instance, an employer has the right to fire under-performing employees, and the right to make the decision about that on their own (as long as their decision does not conflict with other fundamental rights, such as equal protection, that society has recognized). They are explicitly permitted to make bad decisions. A society that only gave you the right to make good decisions would not be a free one; a society that prohibited discussion about whether it was a good decision would also not be a free one.
Basically, relatively few people have a problem with the idea of censorship; a certain amount of moderation is necessary on an Internet forum to prevent shitposting. What people are decrying is misguided, stupid, and / or malicious censorship - either due to juvenile power games on the part of the moderators, or due to an external agenda that said moderators are pushing.