You can disagree with their methods politely/with a proper discussion, targeted abuse at specific members earns you warning points.
It is a simple and should be obvious distinction, please start adhering to it.
Also as it clearly says in the title NOT A PLACE TO ASK FOR UNBANS.
The answer to your question of "Where then" is nowhere, they don't want or need to unban people. Again, you can disagree all you like, but it is their server and their decision so do it in the proper way or it will be you on the receiving end of repercussions.