The courts, not surprisingly, are wrong and that's a distinction without a difference. The whole notion of TouchID verification is predicated on the idea of uniqueness and lack of single-step reproducibility, just like a mentally-held combination or password. Courts have rendered numerous decisions in recent years that are blatantly unconstitutional. It is merely the general acceptance of the population at large, and their unwillingness to engage in broad civil dissent, that allows it to continue. That failure to object does not make it any more legal than blue or segregation laws were.
Actually the judge's ruling made the distinction very clear.
A password requires speech and/or testimony against oneself. It is covered by the 5th.
A fingerprint, just like a DNA sample does not require knowledge or speech. A suspect can be compelled to produce or submit to DNA testing and a fingerprint is no different.
Lock your phone with a secure PIN. Issue solved.