" the efforts made to protect our endangered species create regulations lacking nuance"
Hmmm. USARK's positions tend to lack nuance as well, so I don't know.
On captive breeding, mentioned in the full alert ("(NOTE: Captive breeding is negligibly mentioned in the petition, and “captive-bred” is dismissively used in quotes, thus misleading that all diamondback terrapins in the pet trade are wild-caught.)":
The largest trade is certainly in exported specimens. Since the species was CITES listed in late 2013, about 3200 CB animals were exported. More than 48,000 that were not CB were (legally) exported during that period (and at least a thousand per year were trafficked during some of that period*). So, captive breeding is about 6% of legal trade.
*Another relevant illustration: a pretty major current seller of Malaclemys terrapin was convicted in 2019 of trafficking WC turtles. The illegal movement of native turtles out of the US is common. ESA listed species, not so much.