There being other people who are morally culpable, whether to lesser extent or not, does not absolve Cheney. Let alone he had a signficantlly larger role in the deception and disaster than Congress.Yeah, and the majority of Dems voted to authorize war in Iraq to set that up and were complicit in maintaining the occupation; loads of civilians were killed by drone bombing by Obama in the continuation of that war (Mosul?). There are a variety of perspectives in looking at and chopping up who is responsible for these things. We like to blame those we disagree with, but that's because it feels good, that doesn't mean it's honest. I don't think it's wrong to opine that someone is a bad person, but to demonize them as evil is another thing. Not only is it irrational because people are complicated, but it's also divisive, which I don't think we need.
And I can agree that evil is not usually a useful descriptor for people, but Cheney's banal sort of evil (mostly ambition and hubris) was damaging enough I don't have any issue with people calling him a shitbag. And mind you I think the we invaded Iraq for oil argument is lazy and does a disservice to how much Cheney and others fucked up.