Marty Mcfly is pretty cool, but his parents are losers. George Mcfly is spineless and clueless.
He is at the mercy of Biff. Lorraine is an alcoholic and by all appearances a poor mother. Then Marty goes back in time, alters the past, and his parents become “better” people and Biff becomes a spineless pushover. It’s all well and good, but let’s take a closer look.
Put yourself in the shoes of George, Lorraine, or even Biff. Your life isn’t perfect, but at least you’re you. You are who you are and no one can take that. Even if they kill you, they can’t steal your identity. They can’t rob your essence. But what does Marty do? He alters the past and changes you! And you know what the worst part is? You have no idea that it happened!!! What happened to the old you?
Marty was almost erased from existence when his parents almost didn’t get together (his mom had the hots for him. Another dark element of the movie) . I suggest that his old parents, the losers, were erased from existence when Marty changed the past.
Marty Mcfly is worse than a murderer. He is worse than a sorcerer with the power to steal souls. He is a soul eraser. And no punishment could ever suffice.
(Above, Shang Tsung from Mortal Kombat steals souls)