"...so what's motivating the over-the-top reaction against it?"

The most logical and intuitive answer would be that they know or strongly suspect that it did escape from their lab, or at the very least that they can't prove that it didn't.

Exactly - it's the over-the-top reaction that makes me curious.

Looking at the paper now - you could back a mack truck through some of the holes in their arguments.

Came across this article - haven't delved into it yet but it raises some questions about the honesty of the authors.

https://www.spectator.com.au/2020/04/who-dunnit-who-knows/

Africa could be part of the picture as well. Lot of viruses - lot of Chinese influence - good playground for genomic surveillance.

Btw Dan several links are to the same source - if it's a quote i linked it even if i'd already done it for previous info from that source - so sorry if you wind up reloading the same article