The main thrust of the video with which I can completely agree seems to be that "satire" is used in Lucretius. Clearly Lucretius does "make fun" of opposing schools in a number of passages in the book.
I agree
Obviously I don't agree with that last point, but I can't tell how deeply the book goes into specifically arguing that Lucretius was in fact not a devoted Epicurean attempting to teach Epicurean philosophy, and that instead he was merely a poet following his muse to create a work of art.
What gives you your certainty that this was not the case? I suspect that if Gellar-Goad hadn't written that Size Of The Sun article, which I too like and respect him for, I wouldn't care much and dismiss it as an absurd claim – and anyone can be right one time and wrong another time.