“Outrage” is what people express when they have been wronged. Good people are outraged when someone is wrongly convicted for a crime they didn’t commit. They are outraged when they don’t get a job they deserve. They are outraged when someone steals their money. This outrage is not joyous.
Joyous outrage is when you feign anger to promote a lie, a deception, or simply degrade or humiliate others because you can and there is nothing they can do about it.
And here are some great examples.