You are correct. The Virginia case is the only case that has been heard on this issue and it is not binding on other courts. This is a very unsettled area of law. However, who knows how future courts will rule?
The legal reasoning is the following. The Supreme Court has held that the 5th Amendment protects against compelled, self-incriminating, testimony.
This is plainly compelled and the data could be self-incriminating. So the key legal question is whether biometric decryption constitutes testimony
Courts ask 2 questions when considering if compelled production is testimonial:
1. Does the production involve "contents of the mind" providing implicit testimony about the existence, possession,control,or authenticity of evidence.
2. Are the testimonial aspects of the production a "forgone conclusion" ( Forgone Conclusion doctrine)
The reasoning why biometrics aren't covered by the 5th Amendment is that they flunk the first question. There is no "content of the mind" involved in the collection of fingerprints, DNA,and blood. Thus it doesn't involve testimony ( as currently defined by the courts )
I agree with you that intent should be considered, but unless Congress enacts a statute either changing the definition of what is testimonial, or a specific statute concerning biometrics, this is what the courts go by.
This would then be analogous to requiring one to produce ANY document on which you had written down the passcode for your phone. Doesn't hold water. That means you have to always memorize the passcode. It can never be recorded anywhere that you have access to outside of your secured phone. You see the illogicity of their position when they ignore the intent of securing the intellectual key, whether it is by a series of numbers or with a personalized biometric system. The intellectual INTENT is the key.
Under the Constitution I should be able to take a thread, string it across my door, and tie it on either side, and say this is my SEAL against official government intrusion under the fourth and fifth amendments and it should be sufficient. Under the rule of LAW, and a government run by honorable men, only criminals would break it.
Unfortunately, there are few honorable men left in government, and we are no longer living under the rule of LAW but the rule of MEN, who ignore honor for convenience and whim. This is the very essence of what our battle is about.