Because entertaining the notion that everyone gets input on game balance regardless of experience or skill is beyond moronic.
No, that's desirable. Thinking that only top invite players qualify to have an opinion on balance is beyond moronic. And elitist. And hypocritical at that if you're not invite yourself.
SPUF posts on balance can actually represent the opinions of the pub community in a non-retarded way if there's lots of threads saying the same thing (eg. sandvich nerf).
And you may not have noticed it, but weapons are not balanced for invite. In fact if nobody but top players can properly use a weapon, it is probably not very good (bargain).
For the record, I don't think that the pistol is such a weapon.