We can riducule conspiracies all day long again but it would be useless, because there aren't any of course.
Favouritism & plain Lazio disliking is undoubtably present among referees, there's simply no way around it anymore since this keeps happening time after time after time .....
An elbow in the face gets no card when you are in a Napoli shirt.
A slight fysical duel when the opponent gets unbalanced and a pure balltackle gets you two yellow cards when in a Lazio shirt.

We had tons of situations like tonight last season and already a handfull again this season.
It's very hard to exonarete referees over and over again because in fact there's no need to, simple coincidences are long out the window by now.