Sorry, and it pains me to say it as I'm the patriarch of an OS X family, but: Kids. Their first exposure to computers will be at home. And it'll therefore likely be Windows. My kids don't know Windows, they know OS X and iOS. Sometimes, after they've visited friends, they comment that they played on a computer that "looked weird", but they've never had a problem adapting.

It's that last bit that seems to suggest a "who cares what the OS is, kids don't care" idea. In my view, though, it really doesn't. Kids aren't known to have a higher order of executive function. They'll generally just use whatever the trusted adults in their lives use.

Those trusted adults should be exposing kids to all the options, so that the kids are better prepared to make decisions when their executive function skills catch up.

Was this weird computer they used a Windows machine or was it an old OSX version? :-)

Only kidding. I went to PC World the other day and attempted to use one of the Windows PCs and quickly became angry with Windows 8.1. Seems I have been using Macs for too long (and I used to use Windows daily, now I do but in a VM and it pains me).

Is it not more productive for teachers to teach something they know? If a kid has a question about Linux and the teacher doesn't know Linux, they won't be able to answer the question. Likewise if a kid has a question about Windows and the teacher doesn't know Windows, they can't answer it.

It doesn't matter what system it is, teachers are best at teaching what they already know.

If a teacher only knows DOS, he/she should teach DOS? ;)

I didn't say "should only teach". If your (obvious facetious, I know that) argument actually followed mine, it would say "A teacher only knows DOS, they would be most effective at teaching DOS". Which is true.

The point, though, of the parent commenter was that just because a teacher can teach something "effectively" doesn't mean that something should be taught in the first place.

There are plenty of teachers throughout the United States who are effective at teaching creationism to their students. I think we can all agree that doing so is not healthy for those students.

OK, but doesn't it follow that the kids would be more productive if the teachers know the OS and are able to help out?