Agreed, I could watch it whilst the dogs were doing their ting (till a couple were playing tug-o-war with a rat) but it was when the 'humans' got involved it was a bit sick.
I think it comes from a general disconnection, often as a function of your circumstance / background, as typically with farmers and certainly those who can use the word 'sport' in the death of any animal (even those described / categorised as vermin).
Like, I wonder if someone who has, had or dealt with fancy rats could kill 'wild' rats in that way, like it really was a live 'Whack-a-mole', and if they couldn't, suggesting that it's not the species that's the issue but just your situation with it.
Mum noticed some rats in her back garden and it turned out they had found the spare rabbit food in the shed. Put that in a rat proof container and the rats went away.
Cheers, T i m