Whoa . . . I just had an epiphany in the shower. No, I didn't shout "Eureka!", and I'm not Archimedes. But here goes:

The powders Alliant says will produce less felt recoil (than Red Dot)--Green Dot and American Select--both require a heavier powder charge. On average, around 10% heavier, for a given load. You burn more powder, you buy more powder. Alliant sells more powder, Alliant makes more money. And making more money is a good reason to tout one of their powders over another.

Of course that does leave us with one question: Faster powder=lighter charge=less powder sold=less money for IMI? What are those crazy Brits up to?