[To say Leia finds it difficult to sympathize would be a complete understatement. It's not hard to see some sort of parallel, with Vader raising Galen, and Vader being her birth father, but Leia isn't the type to easily forgive. Or at least not when it comes to Vader and everything he'd done, and not when she had no real chance to process that information before being confronted with Anakin Skywalker here, alive, and with no knowledge of what he does in the future.]

You're allowed to have your own opinions, even if they're something like that. According to Luke, he turned to the light before his death.

[Buuuut she calls bs on that, since she didn't see it and never saw any indication of any light in him at all.]

Personally I don't believe he deserved any peace.