No it isn't. I never said anything about making hiding DNA illegal, just that it is impractical. If you want to map it onto cryptography, I'm making the rubber-hose cryptanalysis argument[1][2]. People are worried about some evil entity going through proper channels for their evilness when there are more blunt and direct ways to get what they want.
This is the "encryption should be illegal because I have nothing to hide" level of argumentation.