Tell them it’s a crime against a person and against dignity and grace in general, to dictate in whom someone should invest their affection and effort. Love can be given to anyone at any time, and suffers not at all. In fact the giver is always better for it.
No one should ever tell anyone who to care for. After all, I’d advise you to eviscerate them rather than invest time in the education, and I’m older and so more entitled to that stance. Humans can be a vile species. Why would anyone invest affection in them. Gross.
You take my point.
Ask them how they’d feel if a coyote ate their dog. Or if the fox ate their serial killer of a feline. Should anyone tell them how to feel about it? No. Should anyone say an animal isn’t worth love or affection? No.
I don’t often resort to swearing in a confrontation, but I swear I’d look them right in the eye and say “Fuck you, you emotionless villain.”