Interesting, As an HA I personally would have never banned someone for a single case of RDM, unless there is more to it. I'm sure a compromise could've been found around the whole "We can't arrest sith". Since Arrests can be out of characters a simple teleport of the sith and just arresting him would've sufficed in my opinion although a rule was broken and technically at the rank Sinister is at its pretty much up to his discretion.
The reason banning seems a bit too harsh in my opinion is that now he has a "recent punishment" which stops him going for staff, as opposed to anyone else who would've RDM'd would simply have gotten an arrest, if its a rule that sith can't be arrested then it should be tweaked because a ban isn't ideal for a single case. In terms of the appeal, its one day and I doubt sinister is going to unban you, so I'm afraid it is what it is.
I thought this shit was an appeal MB lmao, yeah I doubt anything will be done about this regardless