The two main propagators of modern Ultra-Dispensationalism were without any theological education: John O'Hair and Cornelius Stam. William Miller, founder of the infamous Millerites, had not theological education. In Korea in the 1990s a teenager propgated a view of the Rapture that paralleled Miller's in heresy and damage to the cause. Ellen G. White, 7th Day Adventist heretic leader, had no theological education. I could go on and on.
Are you referring to John O'Hair who was a radio preacher in the '20's?
And is this the Cornelius Stam was a missionary (I had to google his name because I wasn't familiar) who was part of the China Inland Mission group. He and his wife Betty were murdered by the communist Chinese army.
I am rather not recalling to whom you might be referring, so further information would be good.
William Miller was a person who just ran off the rails (so to speak) sort of like that David Koresh or Jim Jones.
Of all that you listed, Ellen G. White was the most influential (imo) but I am reminded that her sort have always been around in one fashion or another. Did not the apostle have to confront issues concerning judaizers?
But the larger issues, are such as has infested the Baptist's both from an eschatological and a soteriological views have been from those supposed folks who were educated theologians.
For example: Setting aside the charismatic folks and attending more toward folks who truly had influence among Baptists from the present to the ancients, Tim LaHaye / Hal Lindsey (followed Darby), Billy Graham (chased after popularity and popularized the presentation of the gospel and allowing further infesting of many churches with modernism), J. Frank Norris (desired social change and power), further back in history Pelagius (human determination), and even further back would be Valentinus (gnostic).
These folks had a large impact on the gospel in their time, and the ripples continue to this day.
Here is the basic premise from which I posted:
There will always be those who chase after some powerbroker agenda driven person. For human's seem to be attracted to those who give answers, no matter how foolish.
But, consider that theological error remarkably from those who are educated has a far greater impact, for then there is this certain sense of granted entitlement that an educated person should automatically be able to discern truth, and would never propagate a lie.
So, if the author of confusion wants to cause great havoc in the matter of the assembly, it will be from people adopting a way of thinking that comes not from typically the uneducated, but those deceivers who have education and purpose to establish their own truth rather then that of the Scriptures. Often, imo, this is done with the agenda to detract from a Scriptural view that is opposed to those who want to hold power and authority in their own camp. For example: Jesuit Luis De Alcazar (1554-1613) who schemed to pervert the Scriptures by inventing the preterits thinking.