As a writer myself, while it can sometimes be hurtful--mostly to my pride, to hear someone criticize my work, I would say that most of the constructive criticism actually improves writing. And doesn't that make things better for the writer and reader in the end?

Yes, exactly. I want to be a better writer and that means being able to communicate with my readers as accurately as possible. So if I'm not getting through, then I want to know, so that I can refine my technique.