Neither judge nor jury thought they detected any slightest sign of remorse - except for the fact that he was found, of course. Later. (he left the scene, of course.. a true coward)

My surmise is that, the "issue" pretty much sub-rosa, has something to do also with - the Murican habit of treating even so-called 'pets' as disposable commodities, once their entertainment value drops below that of the next toy to catch the light just right. Likely too - for many other persons (and not just old folks with cats) - their esteem for the animal more than rivals that for any (living?) human contacts. Pets are, at the very least - not duplicitous.

Killing a 'pet' this important to another is - as you say - an act just-short of - murder of the owner. Merely a surrogate then, for intent to murder another.

He got barely what he 'deserved' IMO. You cannot match-up other crimes on some Mohr scale of 'hardness' - which is why we Have judges (unless it is about Drugs - then we have spreadsheets and no chance for a Judge judging).

I also tend to the belief, from all experience: learning how to 'love' a pet, is for most persons: the best training they ever have on the topic. (And those who never can love an animal - are quite less-likely ever to be capable of 'loving' another homo-sap. At all.)

This creep yielded to his Self-Importance / the utter Outrage! that someone might have scratched his New UAV Bumper -- so he went into full-kill mode. Lock the mfucker up indeed. He won't learn shit, of course - but he'll be away long enough to give the rest of the population a small breather from his execrable presence.