We don't use Windows IE ourselves--we are Macintosh people. So, it's not like we are adding this just so we can use it.

Obviously it would be great if those shortcuts worked on every browser, but the feature that those shortcuts use is available only on Windows IE. As far as I know, the *only browser* that they can work the way they do (select a string of text in a textarea, do something to it in Javascript) can be done in Windows IE.