Nonsense. It should be fully public. If the system is well-designed, publicizing the code will not compromise security but will allow people to verify that the election is on the up-and-up. By contrast, if the code is a super-tightly-kept secret, then it becomes impossible for anyone to know whether the code that's being run is legitimate. Even if the source code is made available to auditors, unless they are given full compilable copies there's no way for autitors to confirm that the source code they inspect bears any relationship whatsoever to the code that's actually being used.
That's the point. And the purpose. What you wanna do, make people suspicious of the honesty of the elections? Next thing you know, the courts will end up having to decide what's a valid or invalid vote.