Isn't there also a related question about her choice of the word "extravagant" - i think she brought that up herself in her podcast interview.
My own take at the moment is that the key thing that distinguishes this category is that the desire in question cannot be satisfied - it has no limit. Yes we might consider them to be extravagant, yes we might consider their result to be corrosive. But it seems to me that the crucial first step is to focus on how to identify them in the first place. And there it seems to me that the various texts are pointing to their commonality being that they "have no limit" - they cannot be satisfied - and so as a result pursuit of them is doomed to failure from the very start.
What is to one person and in one situation "extravagant" is very different for another person in another situation, for whom it might be necessary. Drawing the distinction at "simply cannot be satisfied" such as for eternal life would appear to me both more practical and philosophical and consistent with the texts.
In the letter to Menoeceus Epicurus does not explain the principal of the classification:
We must consider that of desires some are natural, others vain, and of the natural some are necessary and others merely natural; and of the necessary some are necessary for happiness, others for the repose of the body, and others for very life.
But Torquatus does in On Ends 1:45, and what he focuses on is not describing it with a negative adjective but pointing out the fact that it has no limit:
Rackham:
One kind he classified as both natural and necessary, a second as natural without being necessary, and a third as neither natural nor necessary; the principle of classification being that the necessary desires are gratified with little trouble or expense; the natural desires also require but little, since nature's own riches, which suffice to content her, are both easily procured and limited in amount; but for the imaginary desires no bound or limit can be discovered.
Reid translation;
...and it is not possible to discover any boundary or limit to false passions.