While I agree that “died” would have been a bit more neutral, killed is not wrong.
A common expression is “It’s not the fall that kills you, it’s the sudden stop at the bottom.”
In this case neither the fall nor the sudden stop are people but they can still “kill” you.
The “living thing” in the quote above refers to that which is killed by the way. It’s the object, not the subject of the sentence.
Weird use of the word “killed”.
They died:
Totally normal use.
Both words are acceptable. Killed is a bit more emotive.
It’s like the difference between big and colossal. They mean the same technically but invoke different feelings.
Is the nature a “living thing”?
My first thought was that they died by gunshot or something.
I’m not a native speaker, but anyway.
While I agree that “died” would have been a bit more neutral, killed is not wrong.
A common expression is “It’s not the fall that kills you, it’s the sudden stop at the bottom.”
In this case neither the fall nor the sudden stop are people but they can still “kill” you.
The “living thing” in the quote above refers to that which is killed by the way. It’s the object, not the subject of the sentence.
No they are the person / living thing referred to in the definition. “Cause the death of a person” not “a person caused the death”
The attempt to cross killed a person / people.