I probably do sound like the colleagues you've worked with. It's not that I think my time is more valuable than everyone else's, but I do this my time is valuable. It sucks that your colleagues have treated you this way. I've worked with colleagues who would interrupt me every ten or twenty minutes, just when I'm getting back into the flow of concentration needed for programming which they broke ten or twenty minutes ago, often for what seem like very simple or trivial things. My frustrations with that probably bled through in my writing.

I also agree with the principle of treating others as I would like them to treat me. Looping that back to the original topic: that is exactly why I strongly prefer not to just receive a, "Hello," with a wait for response in instant messaging, but an initial message more in line with what the article suggests. This is also what I do when sending an initial message for the same reason: I value the other person's time and want to be cognisant of that.