All because of some Karen twat

I missed that, but I can guess the important part.

Stereo Nacht, The guy was running a nonprofit animal rescue and rehabilitation. Peanut the squirrel was his 7-yr-old mascot he raised from a pup. Fred was a recent rescue. A professional photographer reported him for harboring a potential rabid. NY wildlife raided him, took the critters, and put them down.

"put them down" = Killed/murdered/executed

What's the follow on?
Anybody in trouble?
Was it all legal?