May be true, however, I have seen fog on other brand lens also. I don't know Mr. Gandy, but he does have an incentive, shown by his additional statement :
"Now a good case can be made for the inexpensive current production Cosina Voigtlander lens lineup. "

That said, I would rather have a lens without fog or haze. It sounds like if you have or come across an older lens without fog, it isn't likely get fog so it may be worth considering.