Of course. Noone here said that the commit header shouldn't be followed up by a more detailed description. "git log --oneline" displays only the commit header.
Maybe you're mostly referring to some more complex use of --oneline, but to me that seems like more of an argument for not editing useful information out of your subject line to fit the character limit. Of course all other things being equal, a short subject line is preferable to a long one. But if you have to make a choice, I think it's often better to treat the character limit rule as a guideline.
I'm sure I've broken this rule many times, and I'm not aware that it's ever caused a problem.
Of course. It's just a guideline. All I've done is given a justification for the guideline by presenting a common usage scenario (as intended by the authors).
