But words are sloppy, I totally get what you're saying too (:
But some people definitely have an "angry at the world" or "angry in general" feeling. And if you swoop in with a "let's fix the problem that's causing this" attitude, it may completely miss the mark for them. Ask me how I know (:
For some people, a good outlet for anger is venting, and doing something is not helpful. And for others, it's the opposite. People are complicated. We use simplistic words like "anger" which mean different things to different people in different contexts, and misunderstandings ensue.
This is the exact definition of revenge. While revenge carries connotations that we tend to separate ourselves from today -- sounds too barbaric? -- it's fundamentally about justice, and as such is justified and even noble given the right context and expression.