Finding out Kakashi's reasons doesn't change the fact Rin is dead at the hands of their best friend and doesn't change the fact that the laws/physics of this world rewarded Kakashi and Obito for that brutal sacrificial offering. His eye awakening was basically like the world celebrating Rin's death. The same with when Madara killed his brother for his MS to awaken. This world rewards the butchering of your loved ones.
I am sure Obito has convinced himself that nothing Kakashi says will change that although I suspect it may. Why because as I said, he is not a fully grown mature adult. You think it doesn't make sense because you are judging him as if he shares your perspective and as if he was a grown ass man when all this occurred. He is a dumb kid who was brutally awakened from the fantasy that being a ninja and hokage is so kewl.
Put in a real world context you are basically arguing that someone with Post Traumatic Stress Disorder should actually exhibit symptoms of said disorder like impaired judgment. Even worse, you are essentially saying that despite adults having problems dealing with PTSD, you expect a kid to be able to handle it and make completely rational decisions when their main source of comfort during the whole time is basically an old nutter who has basically had PTSD for the past few centuries, lol.