Yes, ZTL is incomplete for herps and fish, and I should have specified 'on display.' However, saying the statement isn’t accurate 'at all' is an exaggeration, especially given the use of 'likely' and the interpretation of 'obscure,' no? ZTL has plenty of entries for zoos in the native range of the species, and there are no past records for it. Again, it is certainly possible the species was on display somewhere otherwise documented and overlooked but I personally feel this is unlikely.
Since, unlike yourself, I haven’t been to the region, my sense of 'obscure' might be broader, and probably more relevant on a global level. It would be great if a Taman Safari, Batu Secret, or Zoo Negara kept the frogs. I personally doubt any of them or similar hold the species and I struggle to see how that is not accurate 'at all'.