This is the most troubling part of the exchange, and I'm still not sure exactly what his sin was.
For all we know, he was only threatening to rape the atheists' children in order to put the fear of God in them. This might fall under the "appearance of evil" proscribed in 1 Thess 5:22. If he were to actually rape them, one would at least hope that none of the children were male, since homosexuality is unambiguously a dreadful sin and a capital crime under Biblical law. But the Bible never singles out pedophilia as especially heinous. As for rape, it is not only acceptable during war but actually commanded by God (Deut 20:14); of course, this really isn't rape any more than killing an enemy soldier on the battlefield is murder. Could the same apply to spiritual warfare? Enemies of God are enemies of God. Perhaps one of our esteemed pastors could look into this.
Greg's promise to make the children "gag on my c***" also raises some interesting questions. Such an act would make them physically unable to cry out, which under the strictest interpretation of Deut 22:24 would require them to be executed along with Greg himself... so long as they were already betrothed and the rape took place in the city.
Is forced irrumatio rape, Biblically speaking? And would the suburbs be considered city or country?
As I said, interesting questions worth exploring. But I'm not yet convinced he did anything wrong.