I'm guessing they didn't fully understand how the word "bias" is used, and intended to say that there is a bias against their product which is sealed. I'm guessing either RBH or earthquake, as subs with passive radiators could arguably be called sealed, and judging from their specs they would be at a output disadvantage against the other subs, especially the RBH sub. It's obviously not Hsu, SVS, Funkywaves, or Rythmik, all companies that would relish being in a shootout like this, even though SVS was a bit reluctant to participate at first. And I don't think that anyone from Salk would send a email like that, they have a pretty good reputation, and their bread and butter doesn't come from subs anyway.
-Lol, wrote all the above before Gene revised his list!