Nothing is 100%. Nothing is black and white.
If you take things literally, it is censorable. But it requires a majority of miners to censor something. You have to get a majority of a worldwide collective of miners to decide that they will not include a transaction. That means no single government or entity gets to decide what can be censored.
If you are talking about illegal or malicious content, that depends on the content providers. It will be very difficult to prevent that from getting on chain, but most, if not all, of the data on the block chain will have to be fed to users through a service and those services have the ability to filter the content based on their local regulations.
The same thing with immutability. Technically it is mutable, or able to be modified, especially near the tip of the chain. Though it doesn’t really make sense economically to even attempt. It is likely that even if there is a reorg, the data contained is still effectively the same, unless it relates to some blockchain consensus issue. Even at one confirm, it becomes very unlikely that your data can be changed. Miners will not be wasting money to try to manipulate data.
As the data moves farther back in the chain it becomes near mathematically impossible to modify the chain because it requires redoing all of the proof of work from that point forward and building more proof of work on top of a modified chain than all of the miners working on the legitimate chain. At scale this becomes more proof of work than any one entity can produce.