In combat blocking an opponents attack is one of the most pivotal (and in some styles the)facets. Fiction, however, equates blocking attacks to being invincible to them. Disregarding the sheer fact that blocking means taking the force and momentum, just on something a little less (and in some examples more)vulnerable. This is probably because of The Law of Conservation of Detail. If you have gone into the trouble of having the punch blocked, why show that it actually did some damage? In Videogames this is so that the engine can be simpler. Some tropes partially owe their existence to this like Punch Catch, Barehanded Blade Block, Not the Fall That Kills You and Punch Parry etc. Sometimes averted by Scratch Damage and guard specific Break Meter. Contrast Unblockable Attack.
Hello, Unknown Troper. You'll need to get known to lend a hand here.