Absurd. Aside from a "burning in the heart" or other such irrational reason, why would one accept the alleged "authority" of any church?
The Scriptures can be analyzed rationally and logically.
Can anyone honestly say that they came to faith in a complete vacuum with only a Bible in their hands? Didn’t you learn the faith from your parents, teachers, pastors, other Christians, etc. first, and only later read the Bible under the "patronage," so to speak, of those people? And, once again, if I am a Calvinist, will I not form my beliefs around the tenets of Calvinism, making John Calvin my magisterium? If you are now patting yourself on the back for avoiding "institutional Christianity" and going with the "pure wheat" of scripture, then you prove your likeness to Calvin, Luther, Zwingly, etc., all the more. Like them, you are setting off to be your own pope, building your own one-man "Christian institution."
Someone somewhere has to make decisions about public revelation that are definitive. Otherwise, we can never claim to know anything. We call those decisions infallible. We can use another word - certainty, assurance - but a rose by any other name smells the same. Protestants have this as well: Calvinists interpret Romans 9 to teach strict Calvinism. If I question that it does, I will be met with correction. If that isn’t an authoritative magisterium, what is it?