Ah, but you are missing the central element - when what is actually an opinion is rhetorically positioned as truth, especially when it includes a slight against others.
Like, "Powergamers are crappy role players." It is actually a personal opinion, but stated as a fact, and is an insult to those who view themselves as powergamers. No, I don't think folks should be expected that the author meant, "In my opinion...." and allow it to slide without comment.
I think that's off a little bit, but close enough for the moment.
Effective communication is not the practice of saying whatever you darned well please in whatever way is convenient for you. It is the practice of considering your audience, and how best to reach them. So, if you know people read emotional content into text, but you choose to write as if they didn't, because it is "too cumbersome"... that's your choice. To bemoan that, yet again, humans acted like humans is rather like complaining that rain is wet.
You don't get to change human nature. You do get to adjust your writing style.