It can only seem justified if you believe you have all the information, all the facts, and full awareness of everything that is happening.
If you believe you have full awareness and yet something is happening against your will, you will be justified in being angry.
If it's really true that, given all the obvious evidence, it seems that someone else is the culprit, then you are justified in being angry.
But if the truth is that you do not really have all the information, or all the facts, and your awareness is actually blocked - meaning there are some facts outside your conscious awareness - then it's possible your anger might be misplaced and unjustified.
When awareness is then increased, it may reveal new facts, such as that you in fact are attacking yourself, or you hired someone to attack you, or you believe you are a sinner and want to get rid of your sin onto someone else. When that information comes to light, you can see that anger is not justified. It's not justified because the basis for it is not true anymore. Given the facts you are now aware of, it doesn't make sense to believe that others are guilty.
It's no longer true that it was someone else attacking you. It was you attacking you and trying to get rid of your self attack by blaming it on someone else. That's what's really going on. That's the full picture. And in that view, you can't be justified in being angry at someone else.
And all attack is self-attack, there is no attack by others, every time you are blaming others you're really not aware of what you're doing to yourself, and you're always trying to get rid of your own self-attack/sin. Meaning, you are NEVER truly in a position where anger is justified.
No-one else is ever anything other than completely innocent. And ultimately your own self-attack is also unreal and untrue and unjustified.
See, beyond the awareness that you really did attack yourself, there is even MORE information that you are not aware of. Even more facts. Fact is, the attack you think you did to yourself that you think was real and true, was not actually real or true and isn't really happening in reality.
Fact is, you cannot sin because you are innocent. So, with that information at hand, that you are innocent, self-attack cannot be justified either. Seeing the senselessness of it, you will drop it.