Luiz -- who was re-signed by Chelsea and since starred in the three centreback defence adopted by manager Antonio Conte -- said talking about bad things did nothing for the beautiful game.
Aguero's frustrations boiled over and he was given a straight red card for the high tackle on Luiz in time added.
The incident sparked confrontations which led to City being reduced to nine men as referee Anthony Taylor sent Fernandinho to the dressingroom.
"I don't like to publicise things. This is not part of the beautiful football," said Luiz.
"Aguero is an amazing player, he scores a lot, he wins a lot. It is better when you talk about Aguero to talk about good things rather than bad things.
"It is quite normal frustration when you don't win the game and I don't like to speak about negative things. It is normal in football -- when you win you be happy, when you lose you be sad."
Regardless of devout Christian Luiz' generous words Aguero faces a four match ban -- on account of already serving one suspension this season -- whilst Fernandinho could face further measures from the Football Association (FA) for shoving Cesc Fabregas into the crowd.
Chelsea's victory sent them four points clear of fourth-placed City after 14 matches.