It's right there, in the distinction you made between Gaspard and Celene.
I'll try to explain again. But I don't want to be forced to defend Celene too much. Nor am I a big Anora fan. But I feel like I'm being put in that category. I'd rather not be.
Celene is flawed, but she also has a mind for various social reforms. That can be worked on easier imo. And her attack on elves were single events. Gaspard (or rather, the Chevaliers) has partook in more systematic injustices. It's in their very institutions to treat elves like crap. It's not some bad strategic or emotional decision on their part, but something that they've actually codified. They see a whole people as deserving of death, whenever they want. They also think it's their right to just rape when they want as well.
So if you do want to clearer definition of malice from me, it's this systematic violence vs losing your sh*t and not handling tensions well. Celene is the latter to me. Probably a lot of human nobles like this.. they may personally befriend elves, but can't handle it politically.
Last but not least, I want these things to change, but at the same time, I enjoy the drama and negative aspects of the setting. If they do change, I hope it's not too quickly... or drastic like Solas.