They doesn't get it. It's not about just public repository hosting anymore -- it's about "social networking" for code. I know, this sounds like hype for anyone except those who used GitHub (or, maybe, BitBucket, but I haven't used it). It's different than just hosting projects.
While I am a huge Git fan, I completely understand their decision to go with Mercurial. It has better documentation, better cross-platform support, and a similar feature set. Git is improving in all these areas, and I use Git for my personal projects, but Mercurial does have its advantages.
I wouldn't count on it. Internally Google uses Perforce for version control (and IIRC git for some public-facing things), and it's been noted that Google's Python style rules and procedures are quite different from Guido's (their style guide actually goes against PEP 8 -- easy way to spot open-source contributions from Googlers, though).
What an odd thing to say. I guess if you're confined to the Ruby/Git communities, it might seem like no one else has any passion, but still...
There's a ton of fantastic work being done in Python and on the JVM, and quite a few vocal fans of hg. I mean, Scala and Closure get a ton of play here. People are doing fantastic stuff with Django, Twisted, Stackless (and bragging about it). There are lots of people (me included) that would probably be using hg full time if it weren't for Github.
It's really important to keep yourself from being cloistered in a single environment, I think. It's awfully easy to miss cool stuff elsewhere if all you give a crap about is Ruby, and probably detrimental to your own learning.
"I think Google is making some bad choices with the technologies that they are choosing to support (Python/Java over Ruby, Mercurial over Git)."
I remember a large portion of Google's codebase has been based on Python/Java when Ruby was not popular back then. How could you say they made a bad choice to support their own infrastructure? As the reason of choosing Mercurial for Google Code, consider the following facts in addition:
0. Mercurial is written in Python (well, some critical parts in C)
1. Google App Engine supports Python first (then Java)
2. GvR works in Google
3. Python adopts Mercurial this year for version control
The road of convenience isn't necessarily the best road for your product.
Looking at how github has exploded, and how much more momentum git has in the community, it's hard for me to be convinced that it's not worth the effort it would take google to support it. I also think they should support hg and bzr.
I think GvR working at Python has something to do with it. If, instead, Yukihiro Matsumoto had gone to work at Google and build a team developing development technologies around Ruby, things might be different. Not that it's that big of a change either way.