As far as I can tell, there isn't anything wrong with the usage. A lot of people refer to males as "sir", and it's appropriate usage in that sense if they don't know your name. I mean, unless you are wearing a huge nametag or something, then I don't see what is so strange about it.
"Sir" is a lot shorter than yelling "hey-you there, in the blue shirt, black jeans, and white shoes", lol.
I just say "excuse me" and if they don't hear me, I tap on their shoulders. Sure, it might be annoying, but in a room full of people who I don't know, it's the safest way for me to go it seems, to make sure I'm addressing the correct person.
They use "sir" in jokes, casually, even to friends they know. It's like saying "man", or "dude" for some.
Also, the demands could just be plain annoyance. Like, if you go into a nice place and just plop yourself down in any old chair, leaning it back, or not caring that it's really close to someone else's chair, and there is CLEARLY enough room for you to move it, people ARE going to get annoyed, because it is plain disrespectful. Just like you might get upset if someone walked into your house and rearranged all of your things.
So I really don't consider that being polite (calling someone "sir"), then turning around and being mean.... because we just have not been given any details to these situations to confirm that.
"Sir" is simply a term of respect-just another word that doesn't really need a mood or attitude following it, it's a formality. Now what boggles me.... is why they still insist on using the word "the" no matter their mood..... (yes, that was supposed to be a joke)
_________________
Sorry about the incredibly long post...
"I enjoyed the meetings, too. It was like having friends." -Luna Lovegood