The author seemed to not understand Popper's response, which was dead on of course. The type of thing that can be falsified is a scientific theory that makes empirical predictions. Falsification is a prescription for how to do science. It can be argued against from a philosophical standpoint, but it makes no predictions and cannot be proven wrong by observation. It's like asking if the 4th Commandment can be falsified -- the compiler gives a type error.
Again, enjoyable read, but this aspect was disappointing.