"...a breach of common courtesy." I thought it was supposed to be about protecting people..."

It's about both. They are not exactly mutually exclusive. Unless there are very strong reasons I believe we have a duty to do both, and see that as an important aspect of the solidarity that we owe to each other.

I quite agree with Steve when it comes to distrusting the term common sense. Just because most people believe something is right or wrong does not imply that I should fall in line - though it may be a reason to reconsider how sure I am in my opinion.