Death threats towards people that use death threats, really?
I don't like the article. Some people are more knowledgeable on a topic than others, "if you aren't in doubt you're probably wrong" doesn't apply there. Not even in general in my estimation.
A better alternative to "you have to sugarcoat all your thoughts by 30% before you speak them out" would be to train people to be better at taking criticism. People get spoiled by a high baseline positivity. I'd like to bring my points objectively without sugar coating, if everyone did that there would be no problem. Now i would have to either pretend to be more nice than i am ( talking behind people's back is a consequence of this), be straight to the point and get disliked by people who are used to sugar coating or keep silent. It usually boils down to the latter. Let me work alone if i can't be my critical self.
Also, this article seems to be mostly aimed at unfair criticism, let me pose the following.
If the criticism is fair and reasonable, it is justified, doesn't have to be nice, and the receiver is at fault if they dislike it.
If the criticism is not fair or reasonable, it is not justified, the criticizer should express uncertainty where applicable, they are at fault as the article suggests.