I wouldn't call it so carved in stone:

1) The note at `ctypes.c_int' (https://docs.python.org/2/library/ctypes.html?highlight=c_int#ctypes.c_int) is meant for explicit conversion - since the entry is about using `c_int' is Python code, not converting something to `int' anywhere in Python's codebase. (thus, eryksun's statement is but a liberal interpretation)

2) 15.17.1.3. (https://docs.python.org/2/library/ctypes.html?highlight=c_int#calling-functions) is a tutorial, rather than reference, section, and as such, is not an authoritative source. And the corresponding reference section, 15.17.2.3. (https://docs.python.org/2/library/ctypes.html?highlight=c_int#foreign-functions) has nothing of the kind.
Basically, when seen in a non-normative text, such a piece of information is interpreted as a "taking into a secret": "this is what happens behind the scenes - so you better understand it - but don't rely on this too much".

Anyway, to produce convincing evidence to change anything, one probably needs to dig up the rationale for the current behaviour and see what adheres to it / if it still stands.

Sure, this violates Python Zen (koans 2 and 12), yet we probably need something better that this to convince core devs that this is a _bug_.