Please stop balkanizing the scientific software development community. Python has excellent wrappers for many other excellent scientific libraries which in turn leverage C and Fortran for high performance computing.
When people say Python, I never know if they mean 2.7, 3.x, or both, or are unaware that there's a difference, or don't realize how much it matters in practice... so a language that has clear forward momentum, focuses on the latest version, and quickly deprecates old versions is pretty welcome.
It's a lot easy to "quickly deprecate" when the ecosystem is small and breakage is acceptable. Let's see how Swift handles the situation at a similar point in it's life cycle. Bear in mind that most criticisms of the Python2/3 situation came from people that wanted less breakage - not more.
The Python community focuses on stability and maintains each major and minor release for a long time so applications built with a particular version of Python continue to work with updates for a long time