personally i dont think anyone should be made to hold a press conference either, but since the rule is there, theres a big difference between hearing from the manager and hearing from the assistant. and the 'rule' is the manager has to do it, so they didnt technically fulfill anything.
and his excuse was pathetic. id have more respect for him if he just said 'im p!ssed off. no press.'
when you think about it, it is probably better that he didn't rock up to the press conference knowing the punishments UEFA hand out for negative comments about referees and that sort of thing. not sure if he'd be able to control his emotions in this situation tbh.