To be fair, it should go both ways: the receiver should assume goodwill but the person writing should try to be overly nice (to compensate for the “tone is hard in text”). Phrases like “it is a lack of vision that makes you believe this” and “you are fundamentally misunderstanding something” are too easy to be interpreted as rudeness. One can do better here. The “Tone is hard in text” argument shouldn’t be used as an excuse 
Anyways, assuming (and hoping) that no one wanted to offend anyone, let’s talk about type declarations again