This is getting disgustingly stupid. I can understand why you're upset, and I encourage you to share your side, but there's no budging on this issue. Zeality isn't the only person who has claim to the site. Regardless of whether or not Zeality would ever agree to making you an admin, I was the one who refused your request in the end. While the content is generally his, much of the actual ownership and cost is on my side, and I have no relationship with you. Why should I agree to allowing you to be an admin of these forums when you wouldn't even be functioning as one? This part of the site isn't even hosted on your server.
You say that it's not a security risk, but what is security? Every admin can make a backup of the forum's database, then view it locally, allowing them to crack everyone's passwords, read every private message, invade every member's privacy and stalk them, etc.
That's not a power that I want to give to anyone without a damn good reason, and symbolic power gestures are not a good reason. Limiting and dividing power is the only real way to ensure security and accountability. There's a reason I insisted Zeality not share his account information with your server with anyone else, including myself. That was for the good of your server, and likewise nobody should know the FTP information for my side of the hosting except for Zeality and myself.
Besides, admins also have all sorts of powers to create havoc. Each admin account is a weak link. Anyone who has a grudge against you suddenly has a new target, and one which you've added a door for them to get through once they've hacked your accounts elsewhere and gotten your most common passwords to try here. Even you yourself would have to fight against the temptation of your own curiosity.
Now if you wanted help with something, maybe a layout or artwork, some custom scripts, fixing a server issue, or even helping you out because someone hacked your server, I'd be glad to assist. If you want to resell hosting and needed some plugs to get new people to sign up, I'm sure Zeality would oblige. However, this sort of power play seems overly political and downright disgusting -- maybe not to you, maybe not even in a pure sense to Zeality, but to me it is.
The bottom line is that the users on this site have a certain rights and expectations concerning their privacy and the security of their private information, and I won't compromise that -- not even for free hosting. I'll buy $100/month dedicated hosting before even considering adding anyone as admin. The community should be able to trust that those appointed won't abuse their powers and have valid, functional reasons for their roles, so that any member can speak freely and openly, and participate fully. I wouldn't even be an admin myself if I didn't have to manage technical issues with the forum that required it.