Why you'd try to properly lap a stone with the 1200 is beyond me. Stu's advice is sound there.
However, as oz says, for generating slurry (which if done regularly also keeps the stone flat) the 1200 is excellent. I've been doing that with mine for what must be 6 or more years now on the recommendation of So Yamashita as well. I also use the 1200 to set bevels.
It's just a common sense thing I think. Stu needs to cover himself as a vendor by making blanket statements. Completely understandable and I'd do the same in his position.
But it definitely doesn't mean you can't rub the 1200 on a hone in a figure 8 pattern.
James.