Kurosaki Ichigo obviously knows nothing about the Shiba Kaien incident. And really, what is Ukitake supposed to say to him?
There was someone I knew who lost the person he most wanted to protect, and after that he didn't want to live, he didn't want anything except vengeance and death. And he found both of those.
He wouldn't say anything at all, except --
And I accepted that, but he had to find his death on Kuchiki Rukia's blade, and that killed part of her as well.
Live a thousand years, and you see things coming round, time and time again.
---