"I have a Mac" as an excuse to not learn something

I realize that Macintoshes are very nice computers. I actually own one and have had them for a long time, but since most of the world runs on Windows, I have one of those, too, and use Windows each day at work. I don't think a week goes by where somebody doesn't have a problem with a public Intarwebs computer or with the catalog and, when I try to walk them through the process, they interrupt me and say, "I have a Macintosh."
I'm never entirely sure what this is supposed to mean. On the surface, it sounds and looks like, "Silly peasant, I shan't soil my delicate fingers on this task. You, my minion, shall do it for me." Or maybe it's slightly apologetic? I remember trying to use Windoze when I was a Mac-only guy and hated being, functionally and temporarily speaking anyway, an idiot. But I don't remember hiding behind a claim of operating system superiority as reason not to know something.
So I end up saying something like "That's cool. Here's how you do it on this computer." I try to not sound mean about it, too.