It depends on your perspective.
Demons are "bad" for two reasons in Exalted. One of these reasons is the same reason that Raksi is "bad" — your morality is utterly irrelevant to them. Even the ones that grasp moral relativism don't give props to the human ethos, because they have no interest in doing so.
This doesn't make them monsters like Raksi, of course. But at that level, the difference between Raksi and Alveua is mostly, Alveua doesn't want to eat people. The fact that people can find some morality in her actions and not in Raksi's is totally irrelevant to her; and if someone came to her and said, "I've discovered that for every person you reforge, the weave of fate is forced to kill a thousand children in agony," she'd look at you blankly. She'd still be waiting for the point.
The other reason is that they're broken, of course. The Yozis very much want to not care about people, for good or for ill, but it's difficult to maintain superhuman detachment when the Exalted turned you inside out, trapped you inside the bodies of your peers, and, as the icing on the cake, short-sheeted your bed. The Yozis are hateful because they cannot forget, and bitter because they cannot forget, and probably distantly astonished that humans are somehow important enough to make them care. All of them, from the Yozis to the First Circles, are fundamentally damaged.
In a way, a good description for what they've lost is the capacity for heroism. It's that thing that stands between Solars and most WoD splats, that thing that lets you be grander than life without being monstrous. Solars can still forge a utopia, although canonically they won't. Demons don't have that option.
They can still be Raksi. (And worse.) They can still be better than Raksi. But they can't be the thing that the people who complain about Raksi would rather Lunars be. There's no healing for them as the world of Exalted stands. And that's why you have the demons that are all about pain and deceit and stuff—-not because it's what they are, but because it's the only direction they can go. They've lost their protagonist slot, more severely even than the Abyssals, and the only way to get it back is to be PCs in a really deviant game. :)
It's worth bearing in mind, when evaluating my opinion, that demons for the Exalted setting are often written by people who are providing antagonists or special effects, and their consensus is going to skew demons towards more horrible stuff. Similarly, I often get assignments that involve the swords & sorcery idea that summoning demons is freaky and dangerous but basically okay, and that they're decent allies for a sorcerer, so I'm going to skew towards making them, well, not so much intrinsically evil as, well, lost, broken, and inhuman to begin with. That makes me a good reference point for understanding demons-as-things-in-the-world, but not so great for understanding demons-as-antagonists.