They made endless stupid plays. Was the coaching poor? Yes, but the players need to take responsibility too.
Stupid plays usually come about from panic. Panic from the pressure, panic from playing from behind, etc.
Outside of the Finland game, the kids on the ice looked directionless and couldn't rally.
They never developed team confidence because they never really played well with leads. The literal men who brought them together didn't help the literal boys who were the ones playing the game.
A few players certainly underperformed or arguably should not have been invitees in the first place. That's not entirely indicative of the remaining what, 70-80% of the roster and it's not on the kids to want to be here but not deserve to be. Team Canada built the team they built.
Team Canada's coaches and decision makers built poorly, coached poorly, and managed poorly. That Cameron challenge was incredibly risky and unnecessary as it was obvious to anyone that they had their foot on the gas at the time and would score a legal goal soon (and did.) With the benefit of hindsight, the 2 minutes lost on the ensuing PK might well have cost the game as much as the dumb Gibson penalty.