"Constructive criticism" is, by nature, helpful or constructive. It should always be received with a welcome attitude. Even if the source is questionable, a wise man can recognize someone who is trying to be helpful. I have bit my tongue in many situations where there was no value in asserting myself. No one likes to tell another person something and receive a, "Yah, I already knew that!" as a response. I've listened to bad advice, knowing it was bad, and said thanks afterwards. There is really no use in correcting some people. "Do not reprove a scoffer, or he will hate you, Reprove a wise man and he will love you."(Proverbs 9:8)
The way I can receive criticism, constructive or not, and be gracious is by knowing who I am. I have no doubt whatsoever in my own identity. This is a powerful mindset to hold. There is literally nothing a person can say to me that will hurt my self esteem or self worth. The problem with people being unable to accept criticism is they don't know who they are, and when someone says something that makes them feel dumb or inadequate or diminished in some way, they feel the need to defend their own fragile ego. They have to be defensive because if they don't publicly prove that the other person was wrong about them they will be forced to believe what that person said. In fact, it is probably a belief that they hold about themselves, deep down, and try to hide from everyone. If they accept the criticism it means that they have believed the sad truth they they were running from. On the flip side, if you are confident in who you are, you see criticism for what it is or what it can be, an opportunity to learn or grow.