Just because they didn't voice their opinions and the cause of their pain, doesn't mean they handled it better.
Itachi had traumatic issues ever since he was a child and has always thought like an adult (which could be detrimental to a young child ie: ignorance is bliss). Futhermore, the slaughtering of his clan definitely took its toll on him. However, I must agree that Itachi did handle his pain better, since he gave himself an ultimatum through Sasuke. He set up an elaborate plan to commit suicide and maintain the Uchiha's honor, which in turn, acted as the much needed closure that he needed. He wanted to die the villain and he did and when he was resurrected, it was even more beneficial, since he died knowing his brother loved him.
As for Kakashi, if Obito had never resurfaced, he would most likely have been depressed for all the hardships in his life (which were quite apparent with the amount of time spent at Obito and Rin's graves (and let's not forget his father)). However, Kakashi was lucky because he had a second chance to fight face to face with his demons. He was able to talk to his father (due to his momentary death when Pain invaded Konoha) and tell him how proud he was of him. And now with Obito alive and the seemingly final villain, Kakashi will be able to gain closure on Obito's sacrifice in the cave by killing him.