As a catholic...
I don't agree with the over the top exaggeration or hyperbole expressed in that statement. I don't think that the Catholic faith is so entirely superior to ALL Protestants that it is like Stephen Hawking compared to a 3rd grader... But the first part of the sentence "The Catholic Church codified the Bible" is historically accurate.
I assume that the person you quoted was either feeling a bit too superior OR using hyperbole to make a point. Another wards, he doesn't think ALL Protestants are Theologically in 3rd grade... but I don't know him..so I can't be sure.
As a Catholic, I do find it STRANGE that many Protestants regard the bible as the "word of God" and follow it as the sole source of authority (Sola Scriptura) and yet pay the organization which assembled it and preserved it from major change, no heed at all.
They want to USE the product of Magestrial authority, but in no way acknowledge the legitimacy of the magestrium.
While I don't think that this means they are 3rd graders and the Catholic church is Stephen Hawking... I DO find it a tad odd in how they manage to separate the two.
I know many claim that the Church was corrupted at some point.. but most can't pinpoint WHEN exactly that happened, the year when things changed or beliefs were compromised Regardless.. the Protestant faiths didn't just reset the clock to just before the Church apparently went wrong..but changed all sorts of things and went well beyond simply correcting the corruption of the church.
Also, I have issues with the subjective "personal interpretation" that the ideals of Protestantism lends itself to. It creates a sort of subjectiveness to the bible which is easily used by non-believers to justify their own non-belief. Ever try to argue with an Atheist who is dead set that the bible teaches X,Y,Z? You can't..because using Protestant ideals.. they have read and interpreted the bible themselves and to THEM,.. this is what it truly says and no one else has the authority to say they are absolutely wrong. At best.. a difference of opinion.
This is one of my many issues with Protestantism.
Ironically.. my wife is Baptist, but her church is actually, pretty close to Catholicism.. the Pastor's in-laws are all Catholics and he has respect for the faith.
Catholic, Wife is Baptist