The initial article kind of missed a few important points. Must have been a deadline to meet for a space-filler I guess?
Amazon's objection wasn't entirely about the ideas of eBook pricing themselves, it was objecting to the agency model Macmillan was trying to put in place that recognizes the "new" technology. Macmillan was trying *to* adapt to new technology - but it would have meant *Amazon* didn't make as much money per copy sold.
Read Charles Stross' analysis of the whole situation for a better idea of what happened - http://www.antipope.org/charlie/blog-static/2010/01/amazon-macmillan-an-outsiders.html
Even better, try the letter Macmillan sent out to agents and authors, there's a copy at http://www.facebook.com/note.php?note_id=282306625809 - note that the agency model was proposing *dynamic* pricing, no different than current markdowns of physical books over time.
As a side note, Amazon didn't pull the same stunt with Hachette - http://www.publishersweekly.com/article/CA6717788.html?desc=topstory
Bill Ray should have done some actual research for the article a little more - I've seen more balanced party political broadcasts.
Amazon is trying to be to publishing what Apple is to people deciding what to run on their i*'s. I don't know about you, but I've got about as much interest in *Amazon* deciding what I get for my books as anyone else does in Apple deciding what you can run on your iPhone or iPod.
As for why SFWA got involved - It's doing what it's supposed to do, and stand up for its members.