Take note that it is not forum regulars doing the complaining, but rather the suddenly spawned alts (likely of alliance mains) trying to make it look like there is horde outcry about it.
Basically, the Horde says that the Alterac Valley map favors Alliance, since Horde have to make it past the bridge chokepoint and the Stormpike graveyard is more secluded and defended than Frostwolf. The Alliance, on the other hand, blame the Horde’s perennial losses on AFK people, a defeatist attitude, and a lack of defense, and note that Horde seemingly has no problems steamrolling Alliance in WSG and AB. In response, the Horde has issued a challenge for Blizzard to flip the AV map and see if the Horde’s win-loss ratio doesn’t turn around.
https://www.engadget.com/2007-06-12-why-does-the-horde-always-lose-alterac-valley.html