He was decimated.  Are we certain that’s the same Jeff Cassman arrested for the Ponzi scheme?  I wonder if SSPX approved his representing their position in this debate.  I don’t see how anyone else could have done any better though.

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About five years ago a friend and I were discussing the brothers, and she mentioned them having some 'good material' and sent a video along for me to review. It was a case for sedevacantism, and their ultimate conclusion was that the conciliar pontiffs do not have the virtue of faith and therefore are not members of the Church (and therefore not popes). They of course discussed the errors of Vatican 2, but only as evidence that those men lack the virtue of faith.
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If I can find the video, I will post it.
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That said, I clearly spoke prematurely. Turns out Cassman is a con-man, too. Matt Fradd has always rubbed me the wrong way and I guess I shouldn't be surprised that he pulled out someone who has literally faked theological credentials to debate someone who literally fakes religious credentials. These people deserve each other.

Okay, well, if you wanted to be objective you would actually seek out what their true position is on the Pope, not paraphrase some hearsay about what your friend sent you years ago. https://schismatic-home-aloner.com/anti-pope-francis-vatican-ii-antipopes/

Second, prove that the Dimonds are "con-men" (and no, don't point to the Eric Hoyle case). I don't necessarily agree with all their positions, but I would argue that they are genuine in their zeal, if not mistaken on some things and their approach on evangelization; albeit, this debate was a proof that Br. Peter isn't necessarily the "uncharitable" "bitter" person he's made out to be.

So now there's degrees to validity? Also, it's not a matter of valid holy orders, for them, but jurisdiction. They do not believe there are any bishops with jurisdiction remaining, that they know of.