It is because even the best written emails will piss someone off.

Even the most well intentioned notes will piss someone off.

And if, like me, you spent years mastering an inoffensive style of writing emails and posts and DMs that could piss no one off, it'll piss you off.

In my opinion, the idea that you can produce some communication that will produce a positive emotion in the minds of those reading it is still just a gamble. You can pull it off by knowing your audience and what will elicit in them the best, most positive emotions. But in the end, you're just self-censoring yourself from saying what you really want to say because it might give someone bad vibes.