Rule 540 - Checking to the Head and Neck Area – A player who directs a check or blow, with any part of his body, to the head and neck area of an opposing player or “drives” or “forces” the head of an opposing player into the protective glass or boards, shall be assessed at the discretion of the Referee, a minor and a misconduct penalty; a major and game misconduct penalty; or a match penalty. When injury occurs, a match penalty must be assessed.
That's straight from the IIHF rule book. You can complain that you don't like the rules that the IIHF enforces, but you can't say that check was 'clean' (within the rules).
There was clearly contact to the head (penalty) and there was a injury on the play (match penalty). I think the supplementary discipline was a bit much (the extra game), but you CAN'T SAY THAT WAS A CLEAN CHECK BY IIHF RULES (the only rule set that applies at the WJC).