A very obscure point. So Bastogne was different from Afghanistan? So was Gettysburg.
The point was the caliber of the enemy, they are fighting a force that is a sporadic nuisance. (Hence, time for fun every now and then.) Sure a bullet from any one of the Taliban can kill you, but the Afghanistan war is like the US Cavalry fighting Geronimo in the South West. Its a low intensity conflict that has many small unit actions. The fighting isn’t as heavy as it was at Gettysburg or Bastogne where there were thousands involved, the fighting was constant, and there was no time to have fun and treat it lightly.