This comment is almost too stupid to deserve a legitimate response, but I'll give one anyway:
The gaming community, like any other, has developed a system of ethics. It is implied that a server owner or administrator does not use administrative powers (which exist to administer the game, not to play it) unless it's in an official capacity. That precludes: using god powers to help yourself, using god powers to help your friends, using god powers to impede anyone else with the exception of hackers/exploiters/rulebreakers... all in ways that impact other players. Spawning items to test build on the north end of the map, or building arenas for events? Not abuse. Spawn-building an admin tower from which to shoot people? Abuse.
The majority of players see this as reasonable and rational, and thus it is, for the majority of the community, implied. There are naturally a lot of gray areas.
If you or someone you know buys a server and wants to do whatever you want with regards to other players and their houses, you can specify that in: server description, server rules, MOTD etc.. Once you do that, it's no longer implied that you won't be acting like a complete and total tool.
But you won't do that, and neither will anyone else. Because the only players who log onto a server where they know the admin has announced he reserves the right to fuck with the players and act like a complete tool are either his friends, his clan, or players who expect to be getting something out of it.
Admin abuse occurs when a tool pretends to be just another server admin adhering to the implied ethics of server management, decides to use god powers selectively in ways that disrupt the balance of the game, and then use the shitty excuse you just posted above. It's a subjective term, meant to be interpreted subjectively, as a way to warn other players away from certain servers. Which I would do for any server admin that said what you just said.
I can rent a server and name it "Survival PVP" and instantly ban everyone that enters for the lolz. Theres nothing I am doing wrong in MY server and not restricted by Facepunch.