I've met some people like this before, and I think this phenomenon has a lot to do with having one's identity closely bound to the code. Any criticism of the code is interpreted as a personal attack. Conversely, the attitude of "I'm so awesome therefore my code must be super important and really important to protect".
I've also seen the reverse - perhaps more. People need advice but don't want to share their code because they are embarrassed by it. They wrote it thinking "no one will ever see this".
By contrast I sell code, so I know it'll be seen by lots of people, so I tend to spend time making sure style is consistent, things are well named, and so on. But equally, to me, it's just code. Feel free to comment on it - there's always room for improvement.
