When it comes to depicting the consequences of evil, the usual responses are either revenge or grief which are both understandable in their given circumstances and contexts where I do recall the story about a dog that got beaten up by people and came to haunt them.
Now as for stories where dogs do get killed to anger people, there ought to be stories about people saving more dogs from further harm and/or dogs surviving and being traumatised by it, but to show more consideration and perhaps any real hope and kindness in such a dark world.
(Just like in real life, there are people who care for abused animals.)
For another matter, it’s if the character’s girlfriend got killed but rather than grief and revenge the character volunteers to save more people from being killed this way. That partly deconstructs some of the problems with women in refrigerators: no regard for the victim, no alternative to revenge and grief.
If it’s true, then there are still other ways of depicting consequences where the character needn’t to be vindictive to be badly affected by somebody killing their pet or friend.