If this were the case, we would have no mental hospitals, no prisons, and no elderly. They would all have no rights to life according to this test.
The cold hard fact is that no judge has the right to decree whether an person lives or dies. Only a jury has that right after a trial in which the 'defendant' has the right to defend themselves, or has the right to a defense provided by a government supplied defense lawyer. Terri has not been given this, she has been accused of no crime.
"The cold hard fact is that no judge has the right to decree whether an person lives or dies."
Unfortunately, you are wrong.
The issue here is whether Terri's appointed legal representative (husband) could direct her care in the ways that he wished (however awful they might be). Technically, the judges have reaffirmed the husband's rights, which is not the same thing as ordering her death (although with the same outcome.
Courts, by the way, have made such decisions for decades (or longer). They would routinely make such decisions if abortion was only available in cases of rape, incest, etc.