Why does it matter? I think your mistake is assuming that people believe the "change the face of computer science" bit. And perhaps this person had a particular reason for putting this up (wanted to show someone), and doesn't actually feel the need to push every line of code they write. I feel like very few people are as obnoxious about it as you describe, but even then - again, so what?

You're more guarded about your code, that's perfectly fine, but not everyone feels that way. Code that's shared has the potential to benefit and inspire others (even stuff some might see as trivial or silly), code that's hidden doesn't. I see nothing wrong with erring on the side of openness (except with account credentials of course!).