All of Star Wars is pretty inconsistent anyway.
By the time of ROTJ Anakin was guilty of child murder, war crimes, betraying his best friend, torture, murdering his own officers, and genocide ? including being complicit to the obliteration of an entire populated planet.
Spousal abuse and murder is just one more box to check, for that character. If you look at it clearly there was never any ?redemption? available to a character with that much blood on his hands, and Luke was an idiot for trying.
But Star Wars has nothing to do with reality, so whatever.
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