Why doesn't it matter? Because. it. is. still. O.b.i.t.o.Why doesn't it matter? Naruto has learned a lot coming to the point he is at. Remember when he wanted to kill Nagato when he confronted him? He remembered what Jiraiya said and got rid of his anger. He did this because he wants to acquire world peace like Jiraiya did. Naruto no longer judges people by their past actions, and Obito clearly reformed. He also admired Obito's new/old qualities.
Naruto is unrealistic in terms of being too forgiving, and since he can sense evil intent, this is a great thing.
That's why.