I believe it is because he no longer needs so many admins due to the private server thing.
Told by Gravy it was because you and Killer2 caused problems. But then surely if you both caused problems then it's unfair that only you got de-admined.
I don't see what problems I caused. I unbanned a guy that did nothing wrong at the time, being Daenth. Killer2 refused to tell anyone what he said, but insisted on telling us numerous times that he said something. If Gravity Cat wants to de admin me for "causing problems" without even telling me first, that's his choice, I chose to become an admin to help administrate the server, not to become friends with anyone.
I have yet to see Killer2 do much except use the /clearspambricks command and admin orb around. Whenever I join I see the server left for stuff while Killer2 works on his own project somewhere far away, then leaves all the crap for another admin to clean up. Basically all he does is use his admin to ban people he dislikes, as seen almost every day, and orb around.
Becoming an admin isn't a perk, it's a change in how your supposed act on a server. Being an admin isn't supposed to just be extra features that other people don't have. Admins shouldn't be sitting their playing the TDM when there is stuff all over. Becoming an admin is taking a responsibility, but no one seems to know that. I had to unban someone who I know well, after he was banned for "spamming" even though he didn't do anything wrong at all.
Before I was an admin, it took numerous IRCs and messages before I could get any admin to clear the crap all over, or ban the people who actually do something wrong, such as excessively teamkill. All the admins were just flying around in their own mindset, not aware of anything else around them. I don't join your server to have a grand time, I join it to keep everyone there from stuffting all over it. Picking your friends to administrate your server doesn't help. I couldn't care less about fancy guns, I can make them myself. I couldn't care less about people "staining my name", who gives two stuffs, but if it matters to you so much, pick better admins.