The problem is that the channel is turned on by default for
world of warcraft eu power leveling. Thus, it becomes monopolized by bored people seeking attention or arguments or whatever. The general idea behind limiting access to the channel is to both limit the audience of the channel and thus make world of warcraft eu power leveling less attractive to troll, and to make world of warcraft eu power leveling so that you are not generally exposed to that kind of nonsense when you're actually doing something in the game.
I just read world of warcraft eu power leveling reasoning and it appears that they simply don't want any global channels because of the potential trade-chatting-chuck-norris-joke-telling buffoonery that would arise. I like the idea of being able to play an alt while you wait for a spot to open up in the dungeon you are queued for world of warcraft eu power leveling. This seems very reasonable. Spot opens up,
world of warcraft eu power leveling gives you a message, and your alt is poofed into the ether and your main is logged world of warcraft eu power leveling in.
It seems to me there's a very simple solution to this and Make a realm-wide opt-in
world of warcraft eu power leveling channel that only allows predetermined phrases. If they only want channels to be used for their intended purpose, and world of warcraft eu power leveling is the easiest one to force that on.