You were calling someone a word that is used as a form of abuse against people with mental disabilities, that is disrespectful and you were warned for it after i had already given a verbal for the same thing. You were punished before the RDMer likely because all staff were busy with reports and yours was still waiting, not like the order in which people are punished matters. So yeah if you still are unsure the rule you broke is bellow.
1.2 Discrimination
Discrimination in any form (sexism, racism, prejudicial remarks) is not permitted on any server. Read this for more information.
1.2a Disrespect
Users of the ZARP community server are to conduct themselves respectfully at all times. This rule is also in relation to rule 1.2