Those are great rankings for the parts of the software development community that use Stack Overflow and GitHub. Here's a hint: those parts of the community are not representative of the community as a whole. Not even close.
I actually felt a bit weird using the word community and considered changing it to something else. Really though, just because they aren't part of SO or GitHub doesn't mean they live in a vacuum. There are tons of other focal points for developers on the web, and that's not even considering local user groups and meetups, etc.