Don't feel bad! I'm sorry, I didn't post that to make you feel bad! You didn't know.
I've only spun tussah silk, and it's a dream to spin. LOVE IT! As with any fiber though, it depends on who processed it. I've bought tussah silk that was slubby (from a vendor at SAFF) and some that was just incredible (from Franquemont Fibers on ebay).
Processing might have something to do with the whiteness, I'm not sure, but from what I've read, it's the controlled diet that results in the finer, whiter silk threads.