Why should pure classes, have an advantage ??

Stumbled upon this post on the forums, by the dear Ghostcrawler.

Ghostcrawler :

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Rogues, mages, warlocks and hunters should be doing the highest dps, if you assume all other things are equal. Other things are never equal. Gear, skill, group buffs and encounter (in PvE) all matter a lot. In PvP, highest damage matters a lot less than specific abilities that let you control or break control.

There will be fights where warriors are on top because the situations favor them. There will be fights where the shamans or priests are on top.

Arms and Fury warriors should be mixed in with Elemental and Enhancement shamans, Shadow priests, Retribution paladins, Feral and Balance druids, and 3 types of DKs. .........

Does this mean that hybrid classes not will be able to push the top dps ? Does this mean that because dualspecc comes, they have a legit reason to say. You have the option to be a tank or healer as well. So you cant be top dps ?
What about the people who did choose to play as retribution all the time, and have no intention to go any other specc. Is that just there loss ?

Leads me back to the "bring the player not the class". If that is there mantra now, will there then be no more dps tjecks ? As if you bring the player, a retribution paladin. But they are bound to make the 5% less damage. Then either you wont make it, or the raid bringing only pure dps classes, will never have a problem with the dps tjecks. How are they gonna balance those encounters ?

Cant figure out why, they dont make all dps make the same amount of damage. Then the player that only wanna play Retribution, have equal terms of performance than every one else doing dps.

I know people now will say, but I play a pure dps class. So I dont have the option to play a healer if I want or a tank. No, you dont. But you never had. I have always had the option to do so. That was one of the reasons I choosed the class in the first place. BUT I have never been able to do it at the same time. BUT why should I then be punished for it ? It brings me to think. Do people play there class because it at the time they rolled it, was the top dps class ? And not because they WANTED to play the class ?

I cant figure out the line in blizzards way to balance the game at the moment. It seems to me that they are between to cliffs. On one side they hold on to the old terms, hybrid dps/pure dps. And on the other side they have the new mantra "Bring the player not the class". And cant seem to dare take the big step and go all out on the new mantra. Am I the only one thinking this ?