Expressing the speakers understanding of the impact that listener had on their emotional state so that it can be addressed is the point of the expression (which is not in exactly the optimum recommended form, but that’s a side issue), so that’s not at all an unintended result.
> It’s an accusatory way of expressing one’s emotional state.
It’s not a way of expressing an emotional state, its a way of expressing a relationship problem, of which the emotional state is a component, but not the central feature. And, yes, the speakers understanding of causation (the feature you call "accusatory") is central to the purpose.
> Nothing straight forward or honest about that.
It is exactly straightforward and honest, provided that it reflects the speakers honest understanding of the relevant causal chain.
Obviously, if that's not the case its not straightforward and honest, but then we are speculating beyond the information provided.
> It’s pure manipulation
No, its not.
