Because Nginx is a very widespread high performance web server that initially seemed not to be impacted but now it turns out that it is.

Except it's only impacted in a pretty non-standard config.

Not that it's not important to disseminate the knowledge, but the chosen title here is deliberatley sensational

It impacts the product, there is nothing sensational about that. If it wasn't impacted that's what they would have said and with Nginx being the tool of choice for many high volume installations you can bet that there are many thousands running in non-standard configs.

There is no new revelation here.