In the email chain subsequent to this exchange Linus even addressed the fact that the contributor would be better off learning about kernel development by focusing on the removal of unnecessary code and clean up.
No one jumps into kernel development knowing everything.
Maintainers need to teach people, not just about the culture and ethos, but about best practices and Linus had taught people constantly.
He has also learned a lot from others. To suggest otherwise is to think that Linus knew everything about kernel development back when he first began Linux development.