I wouldn't trust an article from StarForce to be objective about StarForce, because StarForce is notorious for really bad PR practices. Along with ridiculing customers and outright lying. Not that this makes them different from many other companies, including even UbiSoft themselves.
That said, whatever the reason (and I don't think it's Starforce), it's great that SHIII is selling well. I think it's just because it's an excellent game after all