The same thing happened to the native North Americans too. When the Pilgrims showed up in Massachusetts in 1620, the whole region between there and maine had been reduced in population by 90+% due to a plague inadvertently brought by traders

Not all - it is very likely this large Amazonian civilization perished before the Iberian colonists arrived in the region. For example, these geoglyphs mapped in the (super interesting!) paper are dated 2k years before the Europeans first arrived in Brazil.

The Aquiry civilization (that this paper is about) actually ceased (either due to collapse or people changing their mind about that way of life, who knows) between 850 and 1000 CE.

And WDYM "anyone"? Obviously plenty of people met them and plenty of civilizations derived from them. By the time Europeans got there, the Amazon Basin was home to 5-10 million people (some models push it up to 20 million). I'm sure traces of that culture and history still mark those indigenous cultures today

It really is a strange and horrific metaphor, analogy, and parable about the effects of isolation - made all the more distressing because it wasn't intentional. It was just our broader ancestors going about their business as normal people.

The Amazon rainforest was extensively modified by pre-Columbian indigenous societies. Some anthropologists have even called it a "manufactured landscape". Modern LiDAR mapping has revealed thousands of large geometric ditches, reservoirs, causeways, mounds, and earthen infrastructure.[0][1] Up to 10% of soils are highly fertile man-made terra preta soils and trees like cocoa, acai, and brazilnut show an unnatural "hyperdominance" distribution due to ancient orchards. Many plants throughout show some degree of domestication[2][3]

And some have even proposed a possible human role in the transition of parts of the Amazon from grassland to rainforest about 10k years ago[4]

https://royalsocietypublishing.org/rspb/article/282/1812/201...

You don't achieve a population of 3M people without such extensive landscape modification.

[0] https://www.zmescience.com/science/archaeology/archaeologist...

[1] https://www.sciencedirect.com/science/article/abs/pii/S02773...

[2] https://www.theguardian.com/world/2020/apr/08/humans-living-...

[3] https://www.frontiersin.org/journals/environmental-archaeolo...

[4] https://www.discovermagazine.com/10-800-years-ago-early-huma...