Sure but, in fairness, the HN title is a bit misleading. The paper says that the bodies are emitting light in the visible part of the EM spectrum not that the light is visible. And the intensity isn't really high enough to see the light without instruments.

True, there's an ambiguity in "visible light" between "EM radiation within the visible frequency range" and "EM radiation within the visible frequency range which is of sufficient intensity that we can detect it with our eyes"

But this is independent of the misconception that the radiation observed in this experiment is thermal. Thermal radiation in the visible range at this temperature is much lower in intensity than the biological radiation observed here, but both kinds of radiation are well below the intensity that we can see with our eyes.

Sure, what isn't fair about debating the headline in the comments without reading the article?