More generally, it's clear that a melee attack that does damage on a miss is one which cannot be avoided: the warrior in question always wears down their foe when the attack them. This is not ambiguous or contradictory.
This claim is obviously not true in 4e D&D. Some hit point loss does not tell us that the character has been injured; all it tells us is that the character has been set back. (Consider eg a PC with 130 hp who suffers 10 hp of psychic damage.)
In those cases where hp loss does correspond to injury, it is no different if it comes from damage on a hit or damage on a miss. Either way, the attack caused injury.
Page 276 of the 4e PHB address Attack Results:
When you hit, you usually deal damage and sometimes produce some other effect. When you're using a power, the power description tells you what happens when you hit. Some descriptions also say what happens when you miss or when you score a critical hit. . . .
If the attack roll is higher than or equal to the defense score, the attack hits and deals damage, has a special effect, or both. . .
If your attack roll is lower than the defense score, the attack misses, Usually, there's no effect. Some powers have an effect on a miss, such as dealing half damage.
Page 293 addresses hit points and healing:
Hit points (hp) measure your ability to stand up to punishment, turn deadly strikes into glancing blows, and stay on your feet throughout a battle. Hit points represent more than physical endurance. They represent your character's skill, luck, and resolve - all the factors that combine to help you stay alive in a combat situation. . . .
Powers, abilities, and actions that restore hit points are known as healing. You might regain hit points through rest, heroic resolve, or magic.
This all makes it pretty clear that the purpose of the attack roll is to determine what consequences flow from having declared
this attack using
this power. There is no statement nor any implication that a miss on the attack roll means that no injury is caused. Any hit point depletion
may be injury, but this is not a function of the rules for Attack Results but a function of the rules for effects and for hit point loss. Consider, eg, the 25th level Rogue daily "Hamstring":
Hit: 4[W] + Dexterity modifier damage, and the target takes ongoing 10 damage and is slowed (save ends both).
Miss: Half damage, and the target takes ongoing 5 damage and is slowed (save ends both).
It's pretty clear that, against an ordinary sort of foe, this attack causes an injury whether it hits or misses - whatever the attack roll, the target is bleeding and hobbled. The attack roll simply determines the severity of the injury inflicted. (Against a wraith, say, or a starspawn, then the ability invites more imaginative narration, of course.)
Now if someone insists on narrating nonsense - eg they narrate that the missed attack roll for Hamstring means that nothing physically happened to the opponent yet for some reason they happen to suffer a hobbling effect - that's on them.