The issue is not so much with someone throwing a paper roll and hitting a coach. It's that of precedent. If the league wants this to be the standard then i expect the same punishment every time something is thrown. Forget the incidents that have happened in the past. There won't be a single derby played in Greece with that standard. So I challenge the league to enforce this.
On the other hand, team punishments only make sense when it's a systemic crowd issue (ie when the violent acts are organized). When one person out of 30 thousand throws a paper roll it's impossible to hold a team accountable to that individuals actions. Again I am basing on what I have seen in Toronto. In 2015 the blue jays played the rangers in the playoffs. After a controversial, yet correct call, blue jays fans threw beer cans on the field. The game continued. A year later, again in the playoffs, a fan threw a beer while an opposing player was trying to make a catch, and nearly hit him. There was a witch hunt to find the fan and he was found (similar to how paok found last night's fan). Again the jays weren't punished by the league.