I never silence my critics. I may defer evaluation of their comments, especially my own super-harsh, inner critic, but I would never silence them, since I intend to keep growing as a writer until my last sentence is written.
One of the most valuable things I learned from a lovely screenwriting mentor and several other award-winning writers since then is this: scale your comments to the work. If someone is clearly a beginner, calling out ever error is not going to help them. What are the two or three most important thing that this beginner should notice and work on? If they struggle with adverb abuse, circle the first few and then write a gentle note, like "consider searching your manuscript for all adverbs and evaluating). In my enthusiasm, I'm afraid I buried some work in red ink. But that's not helpful unless you've been asked to do so.
Another valuable thing--never ever start with the criticism. Don't pay lip service, like "Oh I loved your story but it the protagonist was a stereotype." More like, "I loved how your description of the village helped me understand who your main character was, but it did feel a little slow. Perhaps you could cut back on some of the description or move it to a better place in the story?" If you are going to burden someone with your opinion, make sure they can tell how much you valued what was good about it. Because even the very worst hackery has something that's working about it. Do that hard work and uncover it, so the person being criticized can hear the bad news with an open mind. It makes you both a better writer.