Hemingway could never write when he was drinking. Scratch that. Hemingway wrote a lot while he was drinking, but none of it was published because none of it was any good.
Anger has a similar effect.
As a creator, you are a person that feeds consumers, and you mustn’t feed consumers anger. Yes, there are reasons to be angry, good reasons, but don’t let anger evolve into the act of creating.
As a creator, you are a teacher, a role model, you are setting the moral compass of every person who interacts with your work. There are many parents who shirk their responsibility to parent, mostly because they fear the responsibility.
It’s the same with some creators.
They create, but then do not take responsibility for what they are doing.
That said, whatever it is you are angry about, and hopefully it is an injustice, can be addressed by your positive creativity. And it’s perfectly fine to acknowledge this dynamic. What you are doing, when you create something good rather than something bitter and reactionary, is displacing whatever it is that made you angry.
The public only has a consciousness so big.
And when you create something good, and it gets into the public consciousness, there’s less room for whatever it is that made you angry.
So go and create something good, and displace whatever it is that is pissing you off.