Why is writing special?

Cathy Day’s latest blog post is about time and why she can’t help every stray would-be writer who calls her. She has a wealth of online and social media resources, she says, but she has to draw a line somewhere, because she’s experiencing information overload.

When she posted this on Facebook, one of her friends said it reminded her of this NSFW post about why a screenwriter won’t read your script — in short, because he doesn’t have time, he has other obligations, and because your script probably isn’t any good and he doesn’t want to be the one to tell you.

Question: Why is writing so special? You can make fun of someone for being bad at math, but if you critique someone’s writing (or speech), it crushes their spirit. Is it because language makes us human, so by critiquing someone’s language, you’re critiquing their humanity?