[tomkr]

It is perfectly possible to use a deployment-specific version of Python, just like it is with Ruby. But there are organizations where using old technology is (unfortunately) the status quo. This means Django gives you the possibility of still running it in these environments. Hell, there's loads of companies using older versions of Windows and IE. Is it optimal? No, but that's something bureaucracy tends to do.

I am not trying to say Django is a better framework better for making this decision, but it is a decision that makes sense in the Python context, which is careful about breaking backwards compatibility. There's no reason to stop a developer who has that choice to work with Python 2.7 though (this is actually recommended in the FAQ). There is no need to touch the system's Python to do that.