Hypothetically, if the many-worlds interpretation of quantum mechanics were correct, meaning an infinite number of alternate versions of each of us, containing our respective memories and experiences, with the exception of key diverging points that would be unique to each universe, would we be morally responsible for the actions of these alternate versions of us?
If these hypothetical worlds contained the outcome of every combination of every single instant throughout time, surely there would be universes where each of us are cold-blooded murderers, rapists or any other horrible thing you could imagine. Obviously, there would be universes where you and I are never born, as well as universes where we are born, but things diverged so early on that the memories and experiences are not comparable. Due to this, when replying to this question, please primarily imagine universes that were identical to this one up until the time which you are currently reading this; how far would the alternate you need to diverge before ceasing to be "you", if you ever were "you" to begin with.
This may sound absurd to some of you, but remember we are talking about an infinite combination of everything that has ever happened to you, as well as everyone who has ever lived or could have lived.
Note: As stated, this is completely hypothetical, since as far as I could find the idea that a real multiverse would actually contain alternate versions of us is notably unsubstantiated and often disputed.
Edit: My use of the phrase "key diverging points" was in reference to any and all differences between universes. As in, each of the infinite universes being constantly created would have its own unique points in time where something happened that caused the universe to branch off and differ from ours. These key diverging points would be happening continuously and the nature of these points would not be exclusive to any single universe. I didn't think I had to explicitly state this, but it seems I must in order to help some people understand.
Edit #2: One or two of the comments I have received are failing to imagine the infinite possibilities and implications in between the extreme ends of the morality spectrum. Please approach this question with an open mind and avoid dogmatic responses.