Why?

I was reading something at Literal Minded (Neal talking about misinterpreting a question as a speech act) and I went back to an older post he referenced (on where the 'front' of a line is). On that post he had a comment in which he was faux-politely chided for writing "whether or not":

Surely you didn’t really mean to write “whether or not….” A literal-minded fellow like you doubtless meant to write “whether…,” as the “or not” is superfluous in the context of that sentence. I refer you to the excellent article titled “Avoiding the Curse of Whetherornot” at page 41 of “The Scribes Journal of Legal Writing,” vol. 6 (1996 - 1997).

"Curse" seemed a bit strong. Yes, in that sentence it wasn't strictly necessary to have an "or not", but it didn't seem worth fretting over. Some redundancy is always with us, after all. But I was curious, so, since I don't have have that book, I glanced at Google ... and the very first hit on this curse was something called Writer's Block, which offered four situations in which "or not" should never be used. Two of them are clearly okay - one is like Neal's, with only two options and one in fact is clearly an error (Whether or not you drive or take the bus) - but the other two puzzle me.

1. Where the alternatives are immaterial:

* Whether or not literature is available on computer, readers are likely to continue to cherish books.

Prefer:
* Regardless of whether literature is available on computer, readers are likely to continue to cherish books.

3. Where emphasis on both alternatives is desired:

* Whether or not Canadians agree, tax revenues must increase.

Prefer:
* Whether Canadians agree or [whether] they don't, tax revenues must increase.

Can someone out there give me an actual reason (other than peeveology) that Regardless of whether, or Whether Canadians agree or they don't, is is better than whether or not? Either example? Especially that second one, which simply shoehorns in "they do" between the whether and the not?