Clearly you know very little about football otherwise you'd have seen how much time Barnes has been playing in roles where even one goal is a bonus. Strange that the current management team all consider him to be good enough for the Championship but you don't. They are professional football...
If you factor in all of the games where Barnes had been played in any position other than striker fair enough. Barnes, when he gets a run of being played as a striker, will score goals. When he's being asked to drop back to help out defensively not even Messi would score under those conditions...