It isn't about killing him, it's about waking him up. Killing him doesn't matter. If you wake him, he never gets reset, he never goes back to sleep, the warders

It isn't about killing him, it's about waking him up. Killing him doesn't matter. If you wake him, he never gets reset, he never goes back to sleep, the warders you have to kill to wake him never spawn again, and they drop the best loot in the game, so by killing them and waking him up, you remove everyone's ability to grind for that loot, forever. Killing him is a thing that you can only do by using a specific strategy, and doing so has no real effect on anything, he still is awake and you still lose the warders, and therefore the good loot. Since this server is pegged to this specific moment in time when the first two expansions were released, the subsequent content with the better loot will never happen, so now people on this server have lost the ability to get that loot, and they're salty about it.