All of them = the first thread which was an obvious alt account named jake skylynx. Also that account isn't even banned like you claim.
Some people not behaving in the thread = the thread is deleted. How does this make sense? That is clearly on the people using a positive thread, not the thread itself.
Pretending like a discussion won't have opposing views or any criticism is extremely naive but those discussions will almost always lead to solutions and better outcomes instead of most often staff cliques running the show which has been proven to be extremely detrimental.
A discussion thread is pretty needed when there are staff members who just get things wrong all the time. You don't allow people to post things on the actual ban appeals or reports so just allow people to discuss things civilly in a separate thread.