Because gladius finds that if anyone kills him they are apparently cheating. And in the case of staff abusive lets post a little log from the server from today when gladius died and show how it happened.
2012-09-04 23:40:43 [INFO] [PLAYER_COMMAND] JANUARYJONES: /m loggy Loggy, I will pay you 5000 to let me teleport to you when you are by Gladius in a pvp zone
2012-09-04 23:40:57 [INFO] [PLAYER_COMMAND] JANUARYJONES: /gm s
2012-09-04 23:41:02 [INFO] <[36;22m[T][37;1m [37;1mloggy321[37;1m[37;1m> [37;1mlets go[m
2012-09-04 23:41:08 [INFO] <[36;22m[T][37;1m [37;1mloggy321[37;1m[37;1m> [37;1mtele[m
2012-09-04 23:41:20 [INFO] [PLAYER_COMMAND] loggy321: /back
2012-09-04 23:41:22 [INFO] <[37;1m~DeadMau_5[37;1m[37;1m> [37;1mlol dead[m
2012-09-04 23:41:26 [INFO] <[36;22m[T][37;1m [37;1mloggy321[37;1m[37;1m> [37;1mik[m
2012-09-04 23:41:31 [INFO] <[36;22m[T][37;1m [37;1mloggy321[37;1m[37;1m> [37;1mstuff[m
2012-09-04 23:41:32 [INFO] [PLAYER_COMMAND] JANUARYJONES: /pay loggy 5000
2012-09-04 23:41:35 [INFO] [PLAYER_COMMAND] JANUARYJONES: /tpa loggy
2012-09-04 23:41:45 [INFO] [PLAYER_COMMAND] loggy321: /tpaccept
2012-09-04 23:42:05 [INFO] [PLAYER_COMMAND] gladius323: /back
2012-09-04 23:42:11 [INFO] <[37;1m~DeadMau_5[37;1m[37;1m> [37;1mwow what the heck[m
Notice several Important lines
1. A request to Loggy for the teleport (along with payment)
IE the /tpa command
2. the /gm s (thats game mode survival switch)
3. Gladius death (not shown in log, but you see the /back and the "wow what the heck"
4. Also not shown I checked to see if jan was in god mode and she was not, nor did she degod from the time after she killed gladius.
So don't blame your own stupidity on the staff. It gets extremely old and annoying, especially from a person that has been caught using xray and known to lie to staff.
Side note: Getting me annoyed enough to go threw the log and find this (the time gladius gave was 22 minutes off) just to show that there was no cheating is really a waste of my time. If there is a illegitimate complaint then bring it up, but if you bring it up multiple times and every time it is shown for it to be an invalid report there is no reason for us to expend resources on it.