It’s not about conclusively debunking. There is no evidence for it at all! They say he drowned for his impiety at publishing the dodecahedron (stated first by Iamblichus, 700 years later).
“The discovery of irrational numbers is said to have been shocking to the Pythagoreans, and Hippasus is supposed to have drowned at sea, apparently as a punishment from the gods for divulging this and crediting it to himself instead of Pythagoras which was the norm in Pythagorean society. However, the few ancient sources who describe this story either do not mention Hippasus by name (e.g. Pappus)[4] or alternatively tell that Hippasus drowned because he revealed how to construct a dodecahedron inside a sphere.[5] The discovery of irrationality is not specifically ascribed to Hippasus by any ancient writer”
You took initially took issue with the following snippet from the HN article:
> “ Two and a half millennia ago, the Pythagoreans held as a core belief that every number is the ratio of two whole numbers. They were shocked when a member of their school proved that the square root of 2 is not. Legend has it that as punishment, the offender was drowned.”
So I reference a Wikipedia page stating ancient / quasicontemporary sources describe such an event, but those ancient sources didn't attribute it to Hippasus by name. In the centuries after the supposed event authors start attributing this to Hippasus, which is under historical contention, since we don't find this attribution in writings from the same era as the event.
The HN article (just check your own snippet) describe the person as "a member of their school", which is in line with the hermeneutic interpretation of ancient texts (who said what and when).
Perhaps some day newfound libraries will be uncovered, or burnt scrolls deciphered, possibly finding contemporary (in the same lifetime) attributions of this discovery of the irrationality of sqrt(2) to Hippapus.
Basically: oldest sources already describe the events without naming the "offender" that was killed. Currently the oldest sources attributing this "offense" to Hippapus are lifetimes separated from the supposed events, casting doubt on the identity of the victim.
“The discovery of irrational numbers is said to have been shocking to the Pythagoreans, and Hippasus is supposed to have drowned at sea, apparently as a punishment from the gods for divulging this and crediting it to himself instead of Pythagoras which was the norm in Pythagorean society. However, the few ancient sources who describe this story either do not mention Hippasus by name (e.g. Pappus)[4] or alternatively tell that Hippasus drowned because he revealed how to construct a dodecahedron inside a sphere.[5] The discovery of irrationality is not specifically ascribed to Hippasus by any ancient writer”