I think many of the people opposed to the idea have a fun rank or think they're going to get a fun rank sometime soon. I understand your points, but there can also be more exclusive mini-ranks. My argument is that larger ranks should be reserved for, well, actual ranks. It was cool when we had only a few fun ranks, but now there's too many and it's just as meaningless as a mini-rank, if that's what you want to call it.
Distinguishing between the two will make sure no one confuses a fun rank for something only trusted people have, etc.
But I digress, if there's this much opposition to this suggestion, then there's no point in changing it.