It could be a myth anyway, but the article seemed to account for your comment about the pay clock — they specifically said they were trying to “make up” for the pay they do NOT get while waiting for the delay.
So I assumed that while they got zero pay during the delay, that their overtime was based on total hours they had to be available, rather than the hours they got paid, so they might get kicked to “overtime pay” if they had already been “on job” more than 8 hours, even if 2 of those hours were unpaid waiting for the plane to depart.
I don’t know if that is the case or not; I’m just noting that the claim was different than the one you refuted.
The way pay is calculated is rather complex, and the rules change from company to company; the rules for flight attendants are usually different than for pilots. For pilots it is generally a combination of flight time (block to block), duty time (show time until block in time) and total time away from base. But I can tell you that the flight attendants have virtually no control over flight time. Pilots don’t have that much control either. On an eight hour flight, pilots might be able to alter the time +/- 20 min. Pilots do not go into holding patterns for fun, and ATC determines where in the sequence you fit in. They generally decide speed and routes.
I know that neither pilots nor flight attendants (where I work) get overtime pay during delays. The Airline management may have been born at night, but it wasn’t last night.