The pilots are less responsible, imo, than those who were supposed to ensure safe airways.
Notably, the helo’s altitude appeared to be over 100 feet higher than the permissable maximum altitude ceiling given by flight restrictions for helicopters along that Potomac corridor. This would be a pilot error.
Pilots have the ultimate responsibility for safety of flight. Period. Full stop.
That's why they put the cockpit in the front of the aircraft. That assures that the pilots are the first to arrive at the scene of the crash. Keeps 'em on their toes.
On the othrr hand, there's never yet been an air traffic controller killed in a crash of his own making.