We clearly have very different ideas of what "polite" means. Your little exchange makes you come off sounding like a prized asshole.
And, seriously, what kind of unevolved cretin can't communicate without pointing anyway?
This is ridiculous. Pointing serves a very useful purpose in communication, and is often far more efficient than verbal cues. Have you really never pointed at anything while trying to communicate something to someone? If not, you should really try it. You'll be amazed at how easy and effective it is :)
Yes, I know what pointing accomplishes. But it's also very effective to communicate without marking up my screen in greasy finger prints. Everyone — everyone — who thinks that they can point at something on a screen effectively without touching it, is just fooling themselves. You will touch my screen if you point at it, and I'll know you touched it, because your fingerprint will be there, painted in disgusting finger grease distorting my beautiful pixels. Maybe not every time, but most of the time.
There is a place for prized asshole behavior. Frankly, touching someone's screen when it clearly bothers them is pretty damn rude, imo. If the only way to get them to stop is to make them uncomfortable doing it in your presence, that seems fair to me.
I'd react roughly the same way if someone rubbed their genitals on my screen while I was using it. It's that offensive to me. (Actually, I wouldn't mind the genitals quite as much. They're probably cleaner.)
Probably not. There's always a better way to say something. Acting like an asshole is just a fallback for not understanding how to effectively communicate. I'd be annoyed at a coworker if I had the dialogue you posted above with him/her.
And, seriously, what kind of unevolved cretin can't communicate without pointing anyway?
This is ridiculous. Pointing serves a very useful purpose in communication, and is often far more efficient than verbal cues. Have you really never pointed at anything while trying to communicate something to someone? If not, you should really try it. You'll be amazed at how easy and effective it is :)