I’m fairly confident that Hubert P. Yockey has no desire to shutdown scientific exploration into the unknown. I believe he was referring to the confirmation of science theory. There must be overwhelming evidence for such a theory to be “believed” – and I would extend that with the Popper arguments, that the greater the risk-taking in the experiments, the greater the opportunity to falsify, the greater the confidence in positive evidence.
I think you are right about this. That's why his absolute statement needs to be kept in context.
Where have you found his biology lacking?
He isn't a biologist and it's clear from his web writings. I haven't read his book, but a Nature review is critical of his molecular biology. He may be a fine radiation physicist and information theorist.