But no one is forcing you to use that software. There are several lightweight alternatives to all the apps you have mentioned which most of the times can beat the functionality they offer by quite some margin.
-Lashiec
Very true. But when all your peers and instructors use Macs; and all the handouts and examples you are given show a Mac interface; and your formal and ad hoc support networks all think in terms of Macintosh - why fight it? You'll be done in 4 or so years - after which you can switch to anything you want.
As long as they work, there's a lot to be said for standards and platform commonality. In some environments (like a school) almost any standard is preferable to platform chaos, even if it's not an ideal one. A standardized platform removes one unnecessary source of distraction from the mix.
At least so long as it works.
And Macintosh computers (bless their pointed little heads!) do work rather well. So do PCs and NIX boxes. And so do books, pens, paper, and slide rules!
In the end it doesn't really matter what 'gets used' as long as the student is getting educated.

to help his child excel in college without there being an ability to run much software that will distract the child from his studies,
-Innuendo
I'm not sure that's so true any more.
Except for the real diehards, games aren't that big a thing at most colleges these days. At least from what I've seen. The biggest sources of distraction seem to originate on the Internet. And those are reachable from anywhere by any computer regardless of OS.
As long as there's things like Twitter, YouTube, FaceBook, P2P media torrents, chatrooms, e-mail, and porn sites

, the distractions will always be there.
And you won't need to break shrinkwrap to be exposed to them.