Was the Baptist Church Kept “Underground” by the Catholic Church until the Reformation?

You recognize that this minister’s conclusions are not drawn from an examination of the record but from private prejudices. He knows, at least, that the Protestant churches are derived historically from the Catholic Church. His animus against the Church is so great that he refuses to have even the remotest connection with Catholicism. So what does he do? He falls back on the sorry notion that his Church wasn’t founded by our Lord, but by John the Baptist. (Most Baptists don’t believe this, but a few do.) But this causes a problem. In Matthew 16 our Lord says that he “will” (future tense) establish a Church, meaning that John the Baptist, by then dead, could not have established the Church of which Christ is the head. Conclusion? This Baptist minister isn’t a member of the Church Christ founded and isn’t a member of any church derived from it. Does this mean, by his own argument, that he isn’t a Christian at all?