The problem is the same as with openssl's flaws - when we accept all the contributions without detailed code-review we often incorporate code written by over-enthusiastic amateurs (and sometimes even over-confident idiots).
Lots of problem of really open open-source projects (sorry for this tautology) are from the fact that they are open for everyone.
Imagine everyone could commit (without code review) in Haskell compiler tree, Linux kernel or, say, OpenBSD. But in early times of GNU movements this was a very common case.
So, the problem is in the lack of code-reviews, not in GNU movement, let alone Stallman himself.
It is quite easy for ignorant to under-emphasize the importance of GNU tools to what we now call the Internet. It is not just bash, which is very important tool, but in the first place Emacs, GCC, Binutils, GNU make, flex, bison - all the development tools which made possible the raise of early BSD and Linux systems. It is impossible to imagine the world of free, open source software without GNU toolchan.
Nowadays I very much like the example of nginx - it has bigger market share than IIS, while originally was a solo effort, compared to millions of dollars and man-hours which have been spent on development and marketing of IIS. This is how open source model works. Another good example is Erlan/OTP.