Huh? So because you can go longer without food or water than you can without oxygen a feeding tube "isn't a life-sustaining measure" but a vent is? Withdrawing a feeding tube is exactly the same ethically as withdrawing a ventilator.
What Pegita meant was, according to FL law at the time of Terri's collapse, a food tube was not considered life-sustaining while a ventilator was. Several years later, the law was changed to include feeding tubes. The law was then retroactively applied to Terri's case.