The concept of why code does not matter, comes from development management literature. It's not a case of actually meaning "I'm ashamed of the language and the techniques I use". That's an awfully developer-centered point of view.
The influential factors of a successful software project are mainly the quality of the people involved. Next product scope and from there a huge drop down to development process, and finally technology, i.e language.
It's been statistically shown that barring a crazily bad technology choice (Visual Basic for the space shuttle kind of bad), language has very little influence on the success of a project.
That's of course not a nice thing to hear for a developer who's convinced his language of choice is the one true language. Regardless, it's well established knowledge, gained years and years ago through statistical analysis of thousands of projects.