There's two sides to this whole thing.
Yes you are correct, you were treated unfairly because I have seen people in the community say nasty things but it always seemed like there's a very liberal approach to the freedom of expression that's resulting in us not punishing really offensive slurs. Not only you were muted for something others are not getting muted for but the duration seems quite long to as you claim it was done without the warning.
On the other hand you were muted for racism and on the screenshots you have provided you are disrespecting an admin by calling him an 19 yo virgin with an ego boost and a kid.
Our guidelines clearly state that we are allowed to mute for racism without a warning and the suggested duration is not provided so Ciffon didn't really do anything wrong, therefore I would say the report against him is invalid.
What this case brings, however is the fact that we're allowing too much. If people are freely expressing speech of hate, jokingly are not it's nothing good since ignorance is compliance.
To add a note on the "n" word. Me and you are both Polish so we will never fully understand the consequences of using this word and what it means to black people, especially living in the western world. It will be far more respectful if people, not just you refrain from using it.