Read the article again, its not making the passwords case insensitive, merely allowing you to invert the case. i.e. if your password was "aSdf" neither "ASDF" nor "asdf" would work.
Well I feel dumb, sorry. I thought he meant original casing + all lowercase version + all uppercase version were all acceptable (which isn't the same as case insensitive but for the purposes of cracking it is just as bad).
If you don't use Windows you definitely shouldn't feel dumb: if caps lock is enabled on Windows shift will cause you to type a lower case letter, thus inverting what you intended to type rather than uppercasing everything.
I was confused until I realized the caps lock case only applies to Windows users.
I've been using OSX as my primary OS for about a year (other than using Linux exclusively on every machine I SSH into for dev), but I just found out from your post that caps lock + shift doesn't make things lowercase on Mac. So, nope, I have no excuses :P