The problem is that he asked "Why did you do that?" not "Why did you strike him?".........It would stand up because there is no appealing a standard misconduct report, unless they have video evidence! But the wishy washy nature of the report would raise some concerns in the CFA's discipline dept.
Only once have i had a similar situation......first game of the season, i saw a player raise his arm, punch it towards the opponent, heard the contact with the opponents chest, saw the player reaction.......i saw everything about the punch except the actual second the punch connected......i called the offender over and asked why he did that...he replied "he was pulling my shirt and wouldn't let go".....my follow up question was "So you punched him in the chest?"...player "yeah..." Me..."thanks a lot player, off you go!" and promptly dismissed him....no complaints from anyone, good club mark from his team.....