Bigotry is when a person is obstinately or intolerantly devoted to his or her own opinions and prejudices; especially: one who regards or treats the members of a group (such as a racial or ethnic group) with hatred and intolerance. ~Quote from dictionary.
If you are doing those kind of comments, even in private, you are promoting this kind of behaviour. Also, the majority of the times you don't know who is behind the keyboard. So even if there's no intention, there's a negative impact.
We do not tolerate any kind of use of bigoted remarks (racial, sexual, gender, and/or religious discrimination, for example), mainly for the reason stated above. Add to that, it's expressed in the rules you read when you joined the server.
Your appeal will be under review and an answer will be given in the next 7 days.