That comment was completely justified, why would you talk about throwing a cat in a river, what's wrong with you, which is exactly why I said what I did, all of a sudden me saying someone should throw HIM in the river is cruel? Well those are his words, not mine! I Wouldn't even be able to come up with something so sadistic on my own.
You added your own words:
"and you’re never seen again. Kill yourself."
If you had left out that particular phrase, your comment would have been appropriate. Telling someone to kill themselves: inappropriate.
Never try to justify your own poor behaviour by pointing out someone else's poor behaviour.
Done - Algonkin