Yeah and nothing is gained by trashing someone who is dead.
That's where you're wrong. I'm not talking about "trashing someone" I'm just talking about being truthful about who they really were. Why do we learn about all the bad things Hitler, or Stalin did in school, if nothing is to be gained by it? Why not just say, "Oh, they're dead now, nothing can be gained by talking about it."
I know that's an extreme example, but it holds true on a smaller scale too. I don't know if this guy had kids, but I'd hope if he does that people are brave enough to tell those kids about their fathers failings, so that they could learn from it. Not tell them that he was a horrible person just to be mean, but tell those kids the truth, and don't sugar-coat it; that he did make some terrible choices, and did some horrible things, and paid the consequences.