That's not how fault works. At all. Ever. Noticing something and being annoyed is not evidence of anything other than your own emotions.
Here's a word substitution experiment to contemplate: Person A is angry because they noticed person B kissing person C openly in public. Which person is at fault? If you want, we can even say that the kiss was louder than anyone else's kiss, though what that means exactly in this scenario exists purely inside your head.
Here's a word substitution experiment to contemplate: Person A is angry because they noticed person B kissing person C openly in public. Which person is at fault? If you want, we can even say that the kiss was louder than anyone else's kiss, though what that means exactly in this scenario exists purely inside your head.