Having done numerous carbine courses including the CF Gunfighter program, I can tell you that the first sign someone doesn't know how to properly fight an AR platform is the magwell hold. Second would be them taking their trigger hand off the grip to do anything other than clear a complex stoppage.
While I agree with your opinion that a shortened position on the handguard reduces the level of control, it far from indicates lack of skill with any given platform.
It's like saying a pitcher who throws side-arm or any other unorthodox style "doesn't know how to pitch"...



















































