Why would you or anyone be surprised by it? He answered the strawman argument that he was trying to decipher it from someone and the response was then used as an appeal to authority. Decipher could certainly have different meanings than translating it. It could be just deciphering the sounds to a phonetic alphabet. The only relevant point that I saw was that basically anyone that knows basic phonetics could create a phonetic alphabet. If Nelson didn't specifically say he was trying to translate it, why is that strawman argument being asked of experts to discredit him. Just because some might be confused by the semantics and the possibly confusing choice of words doesn't make the strawman argument valid. I am sure there are more qualified people in the world that could probably do a better job of defining the phonetics but it hasn't been attempted by them as far as I know.
It is no surprise at all to me that Krantz would have that predictable opinion. It goes against his absolute faith in gigantopithecus as the ancestor and Grover's ape hypothesis if they had language skills. That absolute faith of his really makes me doubt his understanding of human evolution. It was incomprehensible to me without certain assumptions about his basic philosophical beliefs.
I only know from listening to a few of Nelson's presentations but I never got the impression that he was irrational enough to think he could translate it to English. If he used the terms decipher, I would interpret that as from sounds to his phonetic alphabet. Even that would be extremely difficult and subjective. I wouldn't be much impressed by the conclusions besides the fact that it might have characteristics consistent with a language.