The original cable was published in the meantime [1]. I don't see any mention of "dangerous research taking place in unsafe conditions". Why don't you read it for yourself? It's only three pages.

[1] https://www.washingtonpost.com/context/read-the-state-depart...

To my eyes, this cable confirms what the Politico article said. It says there is a "serious shortage of appropriately trained technicians and investigators needed to safely operate this high-containment laboratory". This is on Page 2, in the last paragraph. As for what's dangerous, Page 3 specifically mentions research undertaken with funding from NIH/NIAID studying SARS-like coronaviruses that can interact with ACE2 (transmittable to humans). Handling such viruses, particularly ones whose infectiousness has been increased (gain of function), in a lab without properly trained staff, seems pretty alarming to me.