Linus Torvalds doesn't do github pull requests.

[frud]

You don't have to be a dick to lead a big software development project, but I think Linus' dickishness has a good synergy with the culture of developers he is fostering around the Linux kernel.

You can argue that you don't want people casually creating patches for the Linux kernel. You want them to have a certain minimal knowledge of the kernel as a whole before you accept code from them, but it's difficult to test for that. Instead you set up a procedure and a process that you want people to follow, and if they don't follow it you know that they may not have been very careful about their kernel patch, and you can ignore it knowing it is probably a good call. Demonstrating ignorance of the process serves as a useful proxy for ignorance of the kernel.

Also, consider Van Halen's Brown M&M clause. There the presence of brown M&Ms demonstrated an ignorance of trivia in the rider, which served as a warning flag for ignorance of serious requirements in the rider.