The RCC's certainty of magesterium vs. Protestantism' "soul liberty"

On pulling evangelicals back from the brink of Catholicism – Mark Galli’s wise words | Grateful to the dead

Thank you Mark [Galli, managing editor of Christianity Today; one can read his article that the post is responding to here], for making the case for evangelical faith in a world that so often makes only the case against it. And for all my students and friends who either have been tempted to, or have actually, jumped to Rome or Constantinople . . . once you have recognized and become disillusioned by the sin that still remains in the church- including the Magisterium- and you yearn once again for the "soul liberty" (thank you, Baptists) that comes from a reliance in the first instance on the Holy Spirit, please come back and . . . if not join us evangelicals again, at least sit at table with us in Christian fellowship. For that fellowship takes place not in our own flesh only, but also in the presence and power of the Holy Spirit....
And thank you, Mark, for speaking to (among others) my bright, anxious students who, straining toward the elusive light of certainty, are finding that the God they serve is not a God of certainty, but a God who demands to be met in the uncertainty of faith. Yes, we will see that elusive light. But not in this life. For now, we see through a glass, darkly. And compared to the surpassing light of the beatific vision, yes, even the Magisterium is as darkness.

My response (currently awaiting moderation):

The problem with a magisterium is that if it if its rulings are in accord with the Bible and the guidance of the Holy Spirit, then it is unnecessary, If they aren’t, then they should not be followed.
Furthermore, I’m not so certain that their decisions necessarily do lead to certainty since it is still possible for a Catholic to question them even if such questioning eventually leads to a split between the individual and the RCC. Otherwise, there would have been no Protestantism.