Sounds like breeder logic, all right. An animal defends itself against a child and the parents punish the animal. From the sounds of it, the kid wasn't pestering the crab and she probably just got too close to it and it gave her a pinch. It happens. Sometimes you get stung by a bee for getting too close to its nest. Well I sure hope revenge was worth the parastic infections (three of them!) from eating some super-fresh crab sashimi. Honestly, he ate the thing whole, shell and all? I bet the shell shards didn't feel too good coming out. But sometimes it's nice to know that there are brain-dead breeders in other countries besides the US.
If the guy wanted to exact revenge, couldn't he have just stepped on the crab? I mean, it still wouldn't un-pinch the child and it would still be animal cruelty. Plus it's not like the crab understood the concept of revenge. Didthe Duh think he'd absorb the crab's power by consuming it or something? In a sense, he kinda did - he acquired the offending crustacean's trio of parasites. Looks like the crab got the last laugh.
Funny how when animals defend themselves against brats, the parents only want to punish those animals if they are smaller. It's easy to beat the piss out of a dog for growling at a brat that's been yanking its tail for 45 minutes, but I've yet to see a breeder climb into the tiger enclosure at a zoo for frightening their snookums and put said tiger in a half nelson.
This article reminded me of something I saw on r/entitledparents. A Moo wants to buy her kid some fish without the proper supplies and the pet store employee refuses to make the sale on that basis, so Moo goes apeshit and the kid gets revenge by eating a crab out of an aquarium (and getting himself stung by an urchin in the process). Of course, being from Reddit, there's a chance it could be bullshit, but breeder entitlement is crazy enough to sound made up sometimes too.
https://old.reddit.com/r/entitledparents/comments/azrznp/little_entitled_crap_eats_crab_in_aquarium_store/