It should be the natural roles of all people to protect innocent life.
Exactly. When you cut through all the peripherals, the first role of government is to protect the governed. To protect among other things his property, his liberty, and his inalienable rights, first and foremost of which is his right to life. Without life the rest of our rights are meaningless. In Terri Shiavo's case the judicial branch of her state's government has abandoned it's duty to protect her life, and has become the leader of those who fervently want her killed for some as yet unknown reason.
God help any poor soul who becomes severely ill or injured while visiting that God forsaken state. The judicial branch of it's government seems to be determined that you will be murdered in your sickbed if you are too sick or injured to cry out for help loudly enough to be heard by TV crews on the street outside your hospital room. What is the voice sound level which qualifies as a plea for life? In Terri's case her cry of "I wannaaaa....." obviously didn't reach the threshold needed to qualify as her plea to live.
IMO this is just one part of the horrible legacy of America's death cultism, which began this reign of terror by legalizing the premeditated murder of unborn children. And it won't stop here unless we stop it. Watch your backs grandpas and grandmas. The death cultists consider you to be nothing more than useless burdens who are hampering their lifestyles, and they are coming for you next.