(I said I’d write A Thing for someone. This is 1.0 in the sense of “part one” and also in the sense of “first draft”.)
When someone is upset or angry with me, I may be upset or anxious or angry too, in response, but:
If they misunderstood what I intended, I don’t blame them for misunderstanding me– I mean, I don’t see it as their fault, I don’t think they need to fix the situation by learning to understand [people/me] better. I misunderstand people a lot too, even when I try my best.
“Just never misunderstand people” is not a realistically possible solution to the problem, so– ideally, at least– there should be a process for clearing up that misunderstanding and fixing its bad effects as much as possible.
If they object to the tone or wording of what I said but not the content, I don’t blame them for being upset by those things. I get upset by subtle, intangible stuff like “tone” sometimes too. I get upset by things that are totally true and necessary to say, but stressful to hear, sometimes too.
“Just stop feeling upset for reasons that aren’t objectively serious enough [by whatever standard]” is not a realistically possible solution. Ideally, there should be a way for both of us to deal with our hurt and still be on speaking terms.