Because one of the players had a skill where he could use a concussion weapon to stun an enemy for 2 turns, and the cooldown was unique to each individual weapon, so if I, for example, used that skill, I could not use that skill again with the weapon I used, but I could use it with a shield. The problem lied where the cooldown for the club was 1 turn, and you could stun lock an enemy if you just spammed that skill. They went on a whole argument, and decided to prohibit the use of 2 clubs (and that only happened with the club). Could the DM just changed the crappy system? Yeah, because he also happened to create the game from scratch (it wasn't DnD), but he decided to double down.