I agree. There are a lot of systems developers who can claim their product is proprietary, but that is meant to protect them from theft on the market, not to protect investigations or courts from seeing how their systems operate if needed.
I agree with the sentiment that source code should be protected, but that is only to protect it from those who would openly study it for exploitable weaknesses. So again, that does not pertain to investigations or court orders.
That is opposite of the cryptocurrency developer's philosophy. The source code to the various coins are open source -- this allows thousands of eyes to peruse the code, so that weaknesses can be detected and fixed.
Whatever the bad actor detects, there are many good actors that will detect the same flaw. Voting software should be open source for the same reason, IMO.