This doesn't really address my point, but the ambiguity arises from the fact that there are often implicit understandings tunneled through standard phraseology that may or may not be intended. We don't know exactly what the Blackhawk crew said. Clearly tower thought they'd be staying clear of the CRJ, but the Blackhawk crew (to some degree) thought they'd be staying clear of some other lights in the area.

Regardless, 91.119 applies (harshly, and unambiguously, in some cases) to significantly safer operations than 75 ft visual separation from passenger aircraft in bravo airspace. That is absurd. Failure was built into the design from the beginning.