Despite being on the list, I disagree with the methodology. Had a discussion about this very thing with my guild yesterday.
You don't evaluate players [dps classes] based on their damage output alone. And no, I shan't bore you with the whole, "they must avoid the fire, not overaggro, etc." side of the argument either, which any decent player is aware of.
Even when evaluating damage alone, damage output is very misleading. It says little about the skill of the player, rather it is a combination of skill, gear, consumables and raid support. Of these, skill accounts for maybe 20-30% of the total. And although gear is easily comparable between players, consumables and raid support is anything but. If you spend 150g+ per raid and go all out with supreme power flasks, immolation oil on CD, summonable pets and etc., while your tanks and healers cater exclusive to your needs and focus on threat and keeping you alive in situations where you shouldn't have survived under normal circumstances, you can easily squash the current rankings.
But what's the point? It's not feasible to do this every raid and it's certainly unsustainable if every player or even the majority of players do it (just do the math, there aren't enough lotuses spawning in real time to support such flask usage alone). Vanilla WoW raiding is a marathon and especially on private servers it's a war of attrition. It's not about who burns the brightest, but who rations their fuel and remains alit the longest.
Even a player with mediocre skill can achieve superior output, if he applies input (gear, consumables, raid support) that is much greater than the competition's. What players should be evaluated on is throughput - achieving the maximum output with the minimum of input. This is where true skill is hidden and as long as people focus on the meters alone, hidden it shall remain.