Luke has come to acceptance with that confrontation, with Vader's words. he had to, if he was going to save Anakin from what he'd become.

"I'm the answer to your question?" He doesn't think he should be anyone's answer, really, he's just a farm kid doing his best at every step to not screw it all up. "And that line, that the truth from a certain point of view, he did that one to me as well, about Vader."