OP: You get the item faster than LFR people, barring bad loot luck. The item, however, is not the sha-touched weapon. What you get faster is the GEM. No one ever suggested that you would get a Sha-Touched weapon faster, nor should you expect to.
As a raider, you already have access to higher ilvl sha-touched weapons. That, and you get sigils faster. So... do you even know what you're complaining about?