I think some of them must love lording over their postions and keeping a power and fear over their congregation
I think this has a lot to do with it. It's left up to the elders to determine the level of repentance using 'Jehovah's spirit'. Since they don't have his spirit anyway, it all boils down to when THEY want to let someone back in. If they're known as 'tough' elders I guess they think they'll have less wrongdoing in their cong's.
I know someone who is still df'd (for almost 2 years now) and they have been studying and making all the meetings. Several months ago she went for her first 'resinstatement meeting' and was told that the elders in her previous cong that df'd her didn't think she was ready. Huh?