Honesty comes first, definitely agree. I don't think that was ever questioned. What was questioned was delivery. Delivery is important because it overcomes the innate skepticism of many people (which can also have emotional and professional ramifications). Honesty and delivery are orthogonal concerns.

Also, the article is about giving feedback, not taking it. The fact that you prefer to take harsh/honest criticism rather than overly-friendly/dishonest feedback is irrelevant (and is also a false dichotomy). You appear to state this to refute any a need to be concerned with delivery at all; your personal preference doesn't change the reality for the rest of society.

So, regarding giving feedback, if your objective is to improve the recipient's chances of success, it behooves you to communicate your (honest) feedback in a way that reduces as much distrust as possible. Techniques for this are given in the article.

But again, I agree, honesty underpins all of this.