If there's one thing the North Korean's don't like, it's having other countries steal away their thunder in the sabre rattling department of propaganda. So, they did what they do best, had some guys punch some bricks.

What do you do when you're a hermit nation that wants everyone to take you super serious? You line up your most special Soldiers and have them punch bricks. Punching bricks alone isn't scary enough though, not when your Russian and Chinese neighbors are also rattling their sabres at the Western World and showing their special Soldiers punching bricks too. You get those special Soldiers to punch bricks with their heads. You get them to punch bricks with their forearms. You get them to punch bricks while laying on spikes. PUNCH ALL THE BRICKS. No one will contest you.

This is how you assert your dominance and show how special your special Soldiers are. No other technique could possibly strike fear into the heart of your enemies. If your special Soldiers can punch bricks this good, surely no one else's special Soldiers will try to stand against them.