What does 人は殺されれば死ぬ People Die If They Are Killed mean?

People die if they are killed is a real Fate/stay night line, and not a mistranslation: in context Shirou is renouncing the ability that made him an exception.

Written
人は殺されれば死ぬ (hito wa korosarereba shinu)
Literally
A line of Shirou Emiya's from Fate/stay night, usually cited as the ultimate redundant sentence. The Japanese says what the English says.
As slang
Not vocabulary at all but a famous line, quoted in English fandom as shorthand for anime dialogue that sounds absurd out of context.
In anime
Spoken in episode 23 of the 2006 series by a character renouncing the ability that let him survive being killed. In context it is a resolution, not a tautology.

People die if they are killed is a real line from Fate/stay night, it says the same thing in Japanese, and it is not the translation failure the internet remembers it as. All three of those facts surprise people.

The line is real

It appears in episode 23 of the 2006 anime, spoken by Shirou Emiya, and it originates in the visual novel the series adapts. The Japanese is 人は殺されれば死ぬ: person, if killed, dies. The fansub that made it famous rendered the words accurately. Whatever went wrong here, it was not the translator inventing absurdity.

The context that got amputated

Shirou has spent the story surviving wounds that should have killed him, healed by a power he did not choose and has come to distrust. The line is his renunciation: he is telling Saber he intends to give that up and fight as an ordinary person, for whom the normal rules apply. People die when they are killed is, in his mouth, a statement about which side of the miracle he wants to stand on. The sense is something like: that is how it is supposed to work, and I want it to apply to me.

A rendering like people are supposed to stay dead when they are killed would have carried it. The literal rendering is defensible word by word and loses the one thing the sentence was doing.

Why it became the joke anyway

Because a screenshot has no memory. Detached from the arc, the line is a perfect tautology delivered with total sincerity, and fandom collects those. It spread through forums as the specimen case of anime dialogue delivered as wisdom and received as comedy, usually alongside the keikaku note, its opposite number: one meme about translating too little, one about translating too literally.

The fair verdict

The famous version is funny and the joke is on the excerpting, not the writing. A boy renouncing his own survival is a serious beat; flattened to one line without its scene, it reads as idiocy. That is not a fact about Fate/stay night. It is a fact about what quotation does, and this site, which is built entirely out of quotation, keeps this page partly as a warning label on the whole enterprise.

Quick answers

What does people die if they are killed mean?

A line of Shirou Emiya's from Fate/stay night, usually cited as the ultimate redundant sentence. The Japanese says what the English says.

Is people die if they are killed an insult?

Not vocabulary at all but a famous line, quoted in English fandom as shorthand for anime dialogue that sounds absurd out of context.

What does people die if they are killed mean in anime?

Spoken in episode 23 of the 2006 series by a character renouncing the ability that let him survive being killed. In context it is a resolution, not a tautology.