I'm going to respond with something I would respond to anyone about this. So, please don't take this personal. It is strictly business.
When you are in charge of something or take lead, you have to accept that role as a leader/boss. In that sense, you can't treat others differently. You cannot include some and exclude others right off the bat or because you don't like them. You can't talk shit about people as a leader either, if you want people to respect you and participate. You must exercise more patience that you would normally.
If they don't want to participate, you can attempt to try things that would entice them. I know you did the FFA but a 3 person FFA I don't think anyone wants to see. That's fine, you tried, and not all ideas are going to be great. So then, you try again. Or maybe in the end, the community just isn't interested. I know the whole master challenge thing has died, so what would revitalize it then?
I know you are going to come back at me with, the admins don't do this (treat everyone equal/respect). But, overall, I believe, from what I've seen, they do a pretty decent job at this. It is very difficult to be a leader with the group we have, I understand that, but the more you give people a fair chance and do not bring other personal issues into your leadership, the more successful you will be. You can still dislike someone and be pissed at them on a personal level, but don't bring it into your leader/boss role.
As a leader, I always start with everyone being equal until they prove me wrong. And that starts from the time I become the leader. Not from 10 years ago.