> I just don't understand why you are apparently not willing to even consider compromises.

I have one thing that I hold immutable here, That os.urandom should use the best interfaces provided by the OS to ensure that it always returns cryptographically random data.

I don't care if SipHash is allowed to use lesser data.
I don't care if os.urandom raises an exception or if it blocks if enough entropy isn't available.
I don't care if people are given an option that will let them maybe get bad data (but will only work on Linux or older *nixes).

All I care about is that the default behavior of os.urandom gets data that is generated using the best practices for that system, because that's what people have been told to use for years and years.