Re: Learn all of them, but NOT Java
"Regarding Python, people seem to assume that just because they use Python, their code is good, even when it is actively terrible."
Not true. The community seeks "pythonic" code showing Python good practice. "The Zen of Python" asks new users to think more deeply about what constitutes good code, (import this). PEP-8 is a style *guide* for readability.
You can write bad code in any language, but blog it for comment and the Python community usually give helpful and constructive criticism. :-)