"Don't feed egregious comments by replying; flag them instead."

a.k.a. Please don't feed the you know what.

https://news.ycombinator.com/newsguidelines.html

The "virus brought in by foreign soldiers during 2019 Military World Games" is a widely used narrative in government of China propaganda.

It's understandable that many people believe it.

It's not just paid trolls ("wumao") who believe this, but even normal people are susceptible to spreading such falsehoods.