Elijah,
I understand and completely agree with your point in asking this, but the problem is a complex one. I, too, am from a generation where being expected to say "please" and "thank you" and calling people sir or ma'am was the norm, not the polite exception. However, that time has come and gone and the world is an ever changing place and with those changes, the moral compass that many people once guided their lives with is becoming a distant memory. And honestly, while it may seem like it, SL is not localized to one nation or even English speaking ones. And, with that cultural diversity comes and even more expansive set of manners and social graces or lack there of.
Many cultures outside of English speaking ones, I have noticed, don't care about how they treat other players nor if they wait their turn or do anything that we would consider common courtesy. It drives me up the wall, to be perfectly honest. My mute list is longer than my arm and seems to grow at an alarming rate!
And let's face it, we're the polite relics from an age gone by, watching a new generation of people who don't hold themselves accountable for hurting others or plowing them over to do or say whatever rude or thoughtless thing they want. Distressing, I know, but it is, unfortunately, the state of the world today.