On the one hand, probably due to simple exposure to so much of it over the years, I don't react nearly as strongly to it as I used to, and generally try to be and succeed in being mature about it.
That being said, however, I WILL take someone to task and make them defend their position for criticizing me if I believe they're wrong or if I have a good explanation - which I often think I do. And as far as I'm concerned, when I'm in that mode, I don't care who the person is or what their intention is, They're my opponent who has attacked me unfairly until the message is either clarified and I can agree with it, or until I convince them as to why my viewpoint, action or work is correct. This often does not sit well with people, especially considering how animated I can get in my discussions and arguments.
Oh, and I absolutely hate the "constructive criticism" excuse! Almost everyone I've found who makes that their defense does so in hopes that they won't have to answer for what they said, no matter how nasty they were being, because they were "just trying to help." It seems to be an emotionally manipulative attempt to disarm the other person so that they will feel too bad about the idea of biting the hand that feeds them, supposedly, and won't object to whatever sort of reaming they get, while all it really does is increase my resentment, that not only is someone laying into me, what I care about and what I've put my heart into, but they expect me to be grateful for them doing so as well. There is a way to make suggestions that doesn't sound abusive or condescending, or at least a way to criticize directly without hiding behind lame pretensions of helpfulness, but said methods often evade those who employ the "constructive criticism" tactic.