The basic principle of Protestantism is sola scriptura, the idea that the Bible is the only infallible rule of faith. Now Catholics have always responded, "Well, what good is an infallible book without an infallible interpreter of that book?" To which the Protestant rejoinder has always been, "Scripture interprets itself, so there!" And then followed the Thirty Years' War, which ended in the ackowledgement that where Catholics have the most gunpowder, that region will be Catholic and where the most gunpowder belongs to the Protestants, that region will be Protestant. If guns can't penetrate the hermeneutic circle, nothing can, and several centuries later the debate over sola scriptura is pretty much the same as it was in 1521.
This means, among other things, that Protestants still insist that Scripture is self-interpreting. Okay, if this is so, then why do Protestants attend Bible School? What can Bible School teach you that the self-interpreting Scripture can't? True, Protestants do acknowledge that the Bible does contain several obscure passages, but these can be deciphered in the light of those passages that, as the Westminster Standards put it, "are so clearly propunded that not only the learned, in a due use of ordinary means, may attain unto a sufficient understanding of them."
The Protestant must say that at least parts of Scripture are so clear that even the unlearned can understand them simply because he can't acknowledge the need for something like, say, a teaching Church. If he did, that would undermine the very essence of Protestantism, namely the rebellion against anything that gets between the believer and the Bible. The Bible should fit the believer tighter than Calvin Klein jeans on Brooke Shields. Furthermore, the Protestant must also say that those obscure passages can be made clear by those parts even the dummies understand. Otherwise, it could not be said that Scripture interprets Scripture.
If all this is the case, then I have no idea why a Protestant has any need of Bible School. The Bible is its own school and clearly comes with its own step-by-step instruction manual. If you are a member of the unlearned, then just start with those dummy-proof passages and work your way up to the obscure ones.
But how are the unlearned to know which are the dummy-proof passages and which are not? Maybe this is what Bible School is for. Maybe students there get Bibles with pages in various colors to denote various levels of obscurity and perspicuity: red for obscure, yellow for somewhat obscure, green for fairly clear, and blue for dummy-proof (and copies of Hustler for the unregenerate). The students spend their class time interpreting the red and the yellow in light of the green and the blue.
But it should be noted that the Bible school is not the Bible. Therefore, it is not infallible. So, it could very well screw up and label obscure passages dummy-proof and vice versa, in which case Protestant Bible school would hinder true understanding of Holy Writ as much as, say, the Whore of Babylon (Protestant speak for the Catholic Church) did and does.
So, I still don't understand why Protestants go to a man-made institution like a Bible School. If they need help understanding and interpreting Holy Writ, why don't they just rely on the Holy Ghost who is supposed to indwell the saved and guide them to all truth. Or, perhaps, if you have to attend Bible School to understand the Bible, then the Holy Ghost does not indwell you at all, and you are really one of the damned. Well, then you might as well save the tuition money, stay home, and gawk at Hustler.