No, people just completely overestimate the killing power of maces and blunt weapons in general.
(one handed) blunt weapons were used to demolish your opponents armour so much that he couldn't fight anymore, not to kill.
Of course two-handed hammers and maces had enough power to snap a neck, but if we're talking one handed blunt instruments, nope, maces are not the knight-killers everyone thinks they are. There is a reason for why most fights ended on the ground, with people being stabbed by armour-piercing daggers, after being completely exhausted.
The only real effective knight killers were the crossbow, the military pick, or any hammer with that crow-shaped spike, and heavy flails.