a pilot's poor decision making
You might think it poor decision making but why did the guy find himself in that position? He didn't plan on commiting suicide, as always there is a story behind the final act, error chain or swiss cheese if you like, nothing occurs in a vaccuum.
Malabo is correct when he posted "Operational control, management guidance, regulatory negligence. Do we as an industry really expect a couple of young R44 tour/instructor pilots to have the experience skill and judgement to attempt a night marginal weather flight through the mountains?"
Pity the bankers didn't opt for an IMC fixed wing, should have taken the merits of using Travel Risk Assessments talk mentioned by
212man.