Disqualification

[wolfpup27]

A player was disqualified during a recent game for a hand to the helmet. The LJ who threw the flag stated that he assessed it to be flagrant due to the fact that the players arm was extended and elbow locked. The player claims that it was incidental as he was swiping at the offensive blocker's arm who was holding onto his jersy, and that the heel of his hand hit the facemask unintentionally. What rule qualifies the LJ assessment to "automatically" make this a flagrant action?