I have a feeling it's not hard to understand the rule, only hard to find "common" sense in it sometimes. The requirement that a flight review is required if a pilot is to fly as PIC is pretty straightforward and plain. But, when it is an impediment for a non-current, certificated pilot who is training for a new category the rule can appear to be unreasonable. I have a feeling too that this is a circumstance the FAA folks had not thought about before. I sure could be wrong though.