In the first camp you have those who think process is important and that it and commit messages in particular are part of the product. Linus Torvalds apparently is such a guy so it makes sense for him to require carefully formatted commit messages as much as it makes sense for me to require four spaces indentation in the code. Apparently Github's tools makes it hard to enforce such strict rules.
In the second camp you have those that consider only the end result, the source code important. For them commit logs are just one tool of many to help them produce bug free code. Consequently, they don't give a flying fuck whether the commit messages uses hard line breaks at the 72 character mark or not. The prettiness of the logs is unimportant.
I'm definitely in the second bucket. Writing commit messages is no fun and adding anal rules to the process makes it even more unfun. Of course, sometimes it is necessary to explain what you are doing, and then you do that to the best of your effort.
Btw, the best way to drive away contributors from a project is to reject patches for silly commit log message formatting rules violations. Linus can get away with it because there are so many that want to contribute to Linux, but projects with lower profile than his would falter pretty quickly if they were so strict about the rules.