The answer has to be far more nuanced than that. There have always been bad popes. Blind loyalty to a bad shepherd does no good for anyone. If the pope violates dogmatic doctrine, should one follow along whistling a cheery tune? One must form a morally mature conscience and actually think, and temper such consideration with a sincere consultation of scripture and doctrine.
Ex Cathedra is Ex Cathedra. Everything else is taken under advisement.
With a bushel of salt.
You’ve got to think of when Father Hardon wrote this in 2002. I dare say it was very true at that time.