"Incompetence" at many levels
Both crews were set up to fail. Considering the near monthly DCA conflicts between helos and fixed wing over a number of years, the surprise is that a midair didn't happen sooner. The data was accumulating, but nobody caught on in time. Not transmitting ADS-B Out in busy airspace and flying in that airspace with night vision goggles restricting view is a major factor. The lack of ADS-B In in the cockpits is another. Then there's the FAA approval of a helo route with inadequate vertical separation from the 33 approach slope along with a lack of ATC procedure to ensure positive separation between helos and aircraft on approach to 33.
Somehow I doubt that all those responsible for those lapses in oversight were female - quite possibly they were all male.