Um, that’s not right.
Extradition is a form of rendition, and “rendition” isn’t a synonym for “kidnapping” (although kidnapping could, and has been, an ugly method of performing a rendition)
Rendition as a single word and legal term just means “transfer”. Legal two-country extradition is a kind of rendition, and “extraordinary rendition” was a euphemism for “way-outside-of-the-usual-laws transfer” (which was most often kidnapping, ie “forced involuntary transfer”).
The word isn’t what made it evil, it’s what they did, without the euphemistically-used neutral word.