In my case, i have extensive knowledge and experience with Windows, OS X and UNIX, as I write software that is run on all three. Most of my colleagues who share a similar or greater depth of knowledge simply don't use Windows, regardless of their ability to do so.
There's no doubt that there's a fervent support base around Apple that has no clue about Windows. Similarly, there's a fervent support base around Windows (and every OS, really), that has no clue about its competitors.
But when I go to software conferences, or look at pictures from conferences, or look at what platforms are used by staff of all the major platform-agnostic tech companies (e.g. Google, Twitter, Facebook, 37 Signals), it's Macs.
So, I don't really think
knowing how to use Windows does anything to promote its acceptance (unless it's the
only think you know). Actually, I think the reverse.
