Why did Sidney Crosby keep playing after scary crash into boards?

About a week ago, Sidney Crosby collided with the back on Matt Niskanen's stick and suffered his fourth concussion in six years.

On Monday night, the Pittsburgh Penguins captain had another scary moment on the ice when crashed head first into the boards during the first period of Game 6 against the Washington Capitals.

Crosby, who sat out a game to recover from his most recent concussion, was agonizingly slow to get up.

It feels like the NHL's concussion spotters were invented for moments just like this, so it's no wonder people are asking why Crosby is still playing in the game.

Before crashing into the boards, Crosby took a stick to the face from his teammate and suffered a bloody nose.

Hockey players are known for being tough but keeping Crosby out on the ice feels borderline reckless.