Robert Hairless, I would be willing to bet that you're not willing to destroy the wall of your gun safe, or the floor of your house. Yet you probably have muzzles pointed at those things right now. Obviously there are common sense exception to rules. Ever been to a gun store? Are the owners of the store willing to destroy all of their display cases? Probably not. Yet their guns are going to be pointed at some part of that display case.
A muzzle always has to be pointed somewhere, even when it's in the gun safe. I'm not willing to destroy anything but bad guys. Since I can't just have my weapon constantly pointed at a bad guy by default just to fulfill Rule 2 to the letter, what's the solution?
That's like saying "All firearms are always loaded" applies to weapons that are field stripped and laying on a mat in pieces. Or weapons that require the the trigger to be pulled(stupid design aside) to be field stripped can never be stripped because that would violate the "Never put you finger on the trigger unless you are ready to shoot" rule.
The 4 rules are meant to stress safety, constant thought and care, and common sense. Not a "ZOMG the 4 rules are 10000% in effect all the time!!!1!!" attitude.