Primarily because that scenario ignores the realities of hyperinflation. Default is bad, but hyperinflation destroys nations.
Also
> won't cause inflation
won't cause HYPERinflation
That's not the claim. Government bonds are like 30 years, so it's not 127% of the GDP all at once. Second, the context was not all debt everywhere, it was Chinese held debt, which is at about 5% of GDP, without spreading it across the duration of the bonds.
> you still haven't posted evidence from an authoritative source.
https://www.theonion.com/fed-raises-interest-rates-in-effort...
Hyperinflation isn't numbers like 10% annual inflation, which are extreme events in functioning economies. Some definitions put it at more like 10,000%. That's not caused by central bank manipulation. That's caused by a complete collapse of the economy. The central bank can try to deal with that by printing almost-valueless currency as an IOU, but that's the result, not the cause.
That's often caused by war, though it's sometimes caused by massive mismanagement of resources. It's not really relevant to the kinds of situations being discussed in the article, which are functioning economies (as long as they can keep from going to war on each other).
Source: Argentina.