[cfcf14]

He doesn't say this directly, but I suppose his comment here:

"The whole 'do an all-nighter to get the paper in the day before the dealine' is something that should have gone out the window after highschool. Not for kernel development."

is making an explicit comparison to the behaviour of young adults (namely: poor time management, crunching for deadlines by staying up late). I agree with you that it's a poor editorialisation and makes it seem like Linus is being harsher than he really is in his writing.

[d0mine]

Unrelated, but in general, a deadline can be used as a tool: avoid unnecessary work, focus. Especially, if it is a soft deadline. It is not just for teenagers, there are whole books on the topic e.g., "The Deadline Effect" by Christopher Cox.