You'r right it's for all damage types, but quote from the wiki ...blockable attacks coming from in front of the player will deal 33% damage for melee attacks and no damage for projectiles.
Since melee attack actually damage the player the armor should lose durablility in this case.
Projectiles on the other hand get blocked completely so the armor should not lose durablility.
MC-98796
You'r right it's for all damage types, but quote from the wiki ...blockable attacks coming from in front of the player will deal 33% damage for melee attacks and no damage for projectiles.
Since melee attack actually damage the player the armor should lose durablility in this case.
Projectiles on the other hand get blocked completely so the armor should not lose durablility.